CA2677895A1

CA2677895A1 - Rocking mechanism

Info

Publication number: CA2677895A1
Application number: CA002677895A
Authority: CA
Inventors: Rui Manuel Quintas Mendes; Joao Maria Luz Ferreira Trindade
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-02-23
Filing date: 2008-02-21
Publication date: 2008-08-28
Also published as: JP2010518960A; CN101616620B; EP2117386A1; CN101616620A; BRPI0807772A2; WO2008103062B1; US20100218312A1; WO2008103062A1; MX2009008988A

Abstract

The hereby presented invention concerns a rocking device that includes a drive mechanism (11,13,14,15) which actuates with an alternative motion one end of an elastic cord (3, 12), which, through its other end, impairs the alternative motion to a carrying handle or any other equivalent attachment point (2) of a baby chair or support or carrying for youngsters (babies) (1), that is adequate for that purpose, being the drive mechanism (11,13,14,15) and the elastic cord (3,12) associated in such a way that, by adjusting its motor (14) idle speed, the frequency of the inducer movement adjusts itself to the natural frequency of the movement induced on the baby chair or support device with the baby. In an alternative version of the invention the rocking device is attached to the baby chair or support device (1) and the elastic cord (3, 12) is fixed to an external attachment point (17).

Description

2 PCT/PT2008/000010 "Rocking Mechanism"
Field of invention This invention refers to a rocking device capable of inducing a rocking movement (oscillatory or pendular) to an infant (baby) chair or support or transport device or to any others to which such movement can be induced, in a new and improved form.

Best art known It is well known that babies are especially soothed by the swinging movement induced to the chairs or cradles where they rest. Recognizing that, many baby chair and cradle manufacturers have adopted curved base designs that allow the induction of a swing movement. Other producers offer chairs or cradles whose support structure is flexible enough to allow that that swinging effect can be induced. The induction of this swinging effect can be achieved either manually or by external devices, in the latter case a drive mechanism is required, being it external to or built in the baby support devices.
It is also known that if that motion is induced with a frequency equal or close to the natural frequency of the chair or support device loaded with the baby, increased movement amplitude is obtained for the same consumed energy or available power, as opposed to the situation in which those frequencies are afar. Chair and cradle manufacturers aim to design their products with a base curvature in a way that the assembly,of the chair or support device with the baby has a natural frequency that is comfortable for the baby, thus seeking the best possible soothing effect for the baby. -Therefore, it is desirable to be able to induce the swing movement with a frequency close or equal to the natural frequency of the assembly.
Several approaches have been made so far to the problem of inducing an automatic swing movement of baby chairs or support devices. For instance, US Pat. Nr. 6 378 940 from J.
Longoria refers to a device able to induce a reciprocal vertical motion to the base of a baby chair, in an adjustable way, to match the frequency of the driving device to the natural frequency of the loaded chair. Other related patents are US Pat. Nr. 5 860 698 from Asenstorfer, etc.

Summary of the invention One of the objectives of this invention is to provide a rocking device that is capable of inducing a swinging motion (oscillatory or pendular) to baby chairs or support devices and to other in which such movements can be sought, in a new and improved way.
Another objective of this invention is to provide a rocking device that is capable of inducing the referred swinging motion to baby chairs or support devices in which such movements can be sought once they have a curved base or a flexible enough structure that allows the swinging motion of the baby.
It is another characteristic of this invention being able to induce the swinging motion both to baby support devices that have a rotation axis or shaft of their pendular movement and to baby support devices that do not have any rotation axis or shaft.
Yet another objective of this invention is to allow a device that is able to induce a swinging motion in a baby support device with the above mentioned characteristics in such a way that it reduces the energy consumption required to induce the movement, by using the energy which is

3 accumulated in the baby support device during its oscillation cycle, and ensuring that the force applied to the support device acts along the whole or part of the descending phase of the oscillation cycle.
To obtain a swinging motion that is smooth and comfortable for the infant and at low energy consumption, it is required that the baby support device is able to accumulate some kind of potential energy. One of the objectives of this invention is its capacity to induce the referred swinging movement to devices that can accumulate either gravitational potential energy, or elastic potential energy.
Yet another objective of the present invention is to allow a device that is able to induce a swinging motion to a baby support device with the above described characteristics in such a way that it ensures that the angular play of the attachment point of the carrying handle will not interfere with the movement thus reducing the smoothness of the motion and comfort of the infant, since there is no impact between moving parts of the drive mechanism nor of the baby support device. As a consequence a low noise level is achieved.
Another objective of the present invention is to allow a device capable of automatically induce a swinging motion to a baby support or cradle with an inducer frequency that may be adjusted in such a way that it adjusts itself to the natural frequency of the baby support device with the baby inside, whichever that natural frequency may be, thus reducing the energy consumption and increasing the working autonomy.
Another characteristic of the present invention is to allow a device capable of imparting a swinging motion to a child support device with the above mentioned features in a way that avoids the need for any external help to start the movement and until it is stabilized, being that movement

4 robust and stable enough without any external help (human or mechanical), thus avoiding the movement to be stopped or significantly reduced due to any baby movements.
Another characteristic of the present invention is that there is a permanent link between the drive mechanism and the baby support device, and the dynamic interaction between the drive mechanism and the baby support device compels the drive mechanism to adjust itself and to vary in each swing cycle in a way that is dependent of the instant load imposed by the baby support device. This entails a smoothness and comfort levels that have not been met by any existing systems or previous techniques.
Another characteristic of this invention is the ability to allow the control of the motion amplitude of the baby support device with the baby inside through the adjustment of the peak or idle speed of the drive in each cycle of the inducer movement, within a certain range of variation of the drive mechanism idle speed, keeping, however, the adjustment of the frequency of the inducer movement to the natural frequency of the movement induced in the baby support device.
Another characteristic of the present invention is its ability, on the one hand, to induce to the loaded baby chair or support device to which it is attached, an oscillating motion of whatever frequency (as long as it is below the natural frequency of the loaded baby chair or support device) by simply adjusting the drive mechanism speed or, on the other hand, to adjust the amplitude of the movement induced to the loaded baby chair or support device (whenever the loaded baby chair or support device is moving at its natural frequency). The former operating mode may be more adequate for very young children, the latter is particularly useful in the case of elder children or those who are more difficult to be soothed.

It is an objective of this invention to devise a drive mechanism that can be easily fitted to existing standard infant chairs or support devices and that can be easily tuned to the desired operating motion conditions, by

5 adjusting the pre-tensioning of its physical link to the chair.
Other features of this invention are to provide a low cost to produce device, being also simple, compact, silent, autonomous and portable, that can provide an effective rocking motion into a baby support device as above described, either as an accessory or built in the support device itself.
The above mentioned objectives are met, in accordance to the invention, with a rocking device with the characteristics described in claim 1.
Subordinated claims define the additional characteristics and beneficial features of the device defined within claim 1.
The invention will be onwards described in detail by means of a currently preferred execution, as represented in subsequent drawings in which:
Fig. 1 represents a side view of a baby bouncing chair associated to the device of the present invention.
Fig. 2 shows a side and top view sections of the rocking device according to the present invention as illustrated in Fig. 1.
Fig. 3 shows a side view of yet another possible concretization of the present invention.
Fig. 4 shows graphically the relationship between the movement of the chair and that of the rocking device as described in this invention, as per the illustration of the floating speed of the inducer movement within each alternative motion cycle.
Fig. 5 shows graphically the frequency variation and the amplitude variation of the movement induced into the baby

6 chair as a consequence of the variation of the idle frequency of the inducer movement.

Detailed description of the preferred execution In Fig. 1, for illustrative purposes only, a baby chair 1 is represented, which features a curved base and a carrying handle 2 to which is attached the strap of one end of the acting cord 3, 12 of the drive device 4.
The rocking device, shown in Fig. 2, consists of a drive mechanism 4, which includes a base box 18, inside which are an electric motor 14, a speed reduction mechanism 11, 13, 15, an eccentric shaft 6, fixed into a regulation slot 10, and an elastic cord 3, 12 whose elasticity is given by a spring or elastomer 12, which is fixed by one extremity to said eccentric shaft 6, and having the other extremity a strap 3 with a loop, which allows its fixation to the carrying handle 2 of the baby chair or to any equivalent fixation point that may be adequate to that function in the baby chair or in any other baby support device.
The speed reduction mechanism 11, 13, 15 consists of 2 pulleys 11 and 15 and by the transmission belt 13.
The eccentric shaft 6 is eccentrically placed on the pulley 11, in a regulation slot 10, through which the rotation movement of the pulley 11 is converted in a reciprocate movement. The eccentric shaft 6 may be regulated within the regulation slot 10 by means of a nut 16, which is tightened to the thread of the eccentric shaft 6. The regulation of the eccentricity of the shaft 6 allows the adjustment of the rocking device to a wide range of baby chair types and baby weights, ensuring that the regulation range allowed by the speed regulation device 7 can always include the optimum working range of the baby chair and baby set.

7 The rocking device includes an electrical energy source, which consists of batteries 9 and to which are associated a connection cable, not represented, as well as a speed regulator 7, associated with the electric motor 14.
The speed reduction mechanism 11, 13, 15 transmits the movement from the motor shaft to pulley 11, and therefore to the eccentric shaft 6, which converts the rotation movement of said pulley 11 to a reciprocate movement of said elastic cord 3, 12.
Said elastic cord 3, 12 may be laid across the box 18, which may, for that purpose, have a passing slot 5. The strap 3 of the elastic cord 3, 12, has the means to conform an adjustable fixation loop, for instance, by means of a "Velcro" band, which can be fixed to the carrying handle 2 of the baby chair or support device, or to any other suitable fixation point of the baby chair, that may be adequate to that need.
The elastic cord 3, 12 is the only connecting element between the inducing device and the baby chair and, therefore, the only inducer of the swing movement. To said elastic cord may or may be not given a pre-stretch by means of the regulation of said strap.
The connection between the rocking device and the baby chair is made in such a way that, regardless of any pre-stretch initially given to the elastic cord, there will never be any ascending force applied to the carrying handle 2, thus avoiding that the play that always exists between the carrying handle 2 and the baby chair may interfere with the smoothness and comfort of the movement, along its angular movement.
Fig. 3 shows an alternative setup where the rocking device is coupled to the baby chair, being the end of the elastic

8 cord 3, 12 fixed to an external fixation point, such as a weight 17, laid down on the base surface.
The rocking device works the following way. The start of the device is done by means of an "On-Off" switch 8, separate or included in the speed regulation device, set to pos-ition "On", being the electric motor 14 fed by the electric power from the batteries 9. Said electric motor 14 rotates and, through the speed reduction mechanism 11, 13, 15, causes the eccentric shaft 6 to rotate. The rotation speed of the electric motor is regulated by the speed regulation device 7.
The rotation movement of the eccentric shaft 6 causes the upper end of the cord 3, 12 to have an reciprocate movement, whose vertical component of descending way, will induce the desired swing movement of the baby chair. The elastic cord 3, 12 will, during the movement, adjust itself to absorb the different distances between its end fixation points, caused by the instantaneous phase differences between the movement of said eccentric axis 6 and said carrying handle 2, with the cord 3, 12 transmitting an oscillatory vertical force to the descending way (or alternatively to the ascending way) which induces the angular displacement of the carrying handle 2 thus producing a swing movement of the baby chair with the baby.
The way the rocking device works differs between the situation where the idle frequency of the inducing movement is lower than the natural frequency of the baby chair with the baby inside, and the situation where the former frequency is higher than the latter. The differences in the working mode between these two situations are graphically shown in Fig. 5.
When the idle frequency of the inducer movement is lower than the natural frequency of the baby chair with the baby, the chair will react with a frequency that is equal to the

9 frequency of the inducer movement, whichever it may be, being the amplitude of the induced movement approximately the diameter of the eccentricity of the eccentric axis 6.
When the idle frequency of the inducer movement is equal or higher than the natural frequency of the chair with the baby inside, it is the frequency of the inducer movement that adjusts itself to the frequency of the induced movement. In this situation, to obtain the self-regulation of the electric motor movement in order to achieve the synchronism between the frequencies of both inducer and induced movements, it is required that the electrical motor has a sensible loss of rotation speed, when it is dragged by the traction force of the cord, adjusting itself that way the frequency of the inducer movement to the frequency of the movement induced in the chair. Under load conditions and in a situation of synchronism with the induced movement, the inducer system shows a speed variation along each cycle that is determined by the load to which it is submitted. Within a certain range of peak electric motor speed, the variation of the inducer movement speed adjusts itself automatically to the natural frequency of the induced movement, in such a way as to maintain the synchronism between both movements. It is possible to regulate the amplitude of the movement induced in the baby chair by changing the instantaneous (or peak) speed of the electric motor in the fastest part of the cycle by means of a speed regulation device associated to the electric motor, without loosing the synchronism between both inducer and induced movements.
The speed regulator 7 allows the manual regulation of the electric motor's rotation speed and, therefore, the peak speed (maximum instantaneous speed of the inducer movement), in a way to synchronize the frequency of the inducer movement with the natural frequency of the movement of the baby chair with the baby.
Fig. 4 represents, in graphical way, the variation of the eccentric axis rotation speed, along each cycle, when the 5 idle frequency of the inducer movement is equal or higher than the natural frequency of the baby chair with the baby, knowing that the carrying handle 2 of the chair with the baby has a simple oscillatory movement which is not represented in Fig. 4. In a first phase, the eccentric axis

10 accelerates until the motor 14 reaches its idle or low load speed. That speed is maintained until the elastic cord 3, 12, through the action of the ascending movement of the carrying handle 2 of the baby chair 1 with the baby starts to apply a sensible load to the eccentric axis. This load has the effect to decelerate the inducer movement, and may even cause an instantaneous stop of the eccentric axis 6. As the swing movement of the baby chair 1 with the baby continues, the carrying handle 2 of the chair starts moving down, causing the distance between the carrying handle 2 and the fixation point of the elastic cord 3, 12 to the eccentric axis 6 to shorten, thus reducing the load applied to the eccentric axis 6, which causes the inducer movement to accelerate again.
If the idle (with no load) speed of the eccentric axis 6 is high (corresponds in the graph of Fig.4 to the curve with the highest top speed), the speed curve shows a bigger slope on the acceleration zone and the reached top speed is higher, thus impairing a bigger impulse on the end of the cord (which also happens earlier in the movement cycle) and leading to a bigger amplitude of the movement induced in the baby chair 1. If, otherwise, the idle speed of the eccentric axis 6 is lower (corresponds in the graph of Fig.4 to the curve with the lowest top speed), the reached top speed is

11 lower, such as the impulse impaired to the cord 3, 12 (which happens later in the movement cycle). That way, the amplitude of the movement of the baby chair 1 will be smaller.
The adjustment of the idle speed of the eccentric axis 6, by means of the speed regulator 7, allows the adjustment, through the above described processes, of either the frequency (when the idle frequency of the inducer movement is lower than the one of the induced movement) or the amplitude (when the idle frequency of the inducer movement is higher than the one of the induced movement) of the movement induced in the baby chair 1 with the baby, and keeping in the latter case the adjustment of the frequency of the inducer movement to the natural frequency of the induced movement.
It will be appraised by the specialists in the art that numerous variations and/or modifications of this invention can be made, as shown in the specific concretizations, keeping the spirit or the scope of the present invention as widely described.
In another development of the invention, not represented, the electric motor 14 may be chosen or setup to have a rotation speed low enough to allow its direct connection to the pulley 11, thus excluding the need for the speed reduction mechanism 11, 13, 15.
Yet in another development of the invention, not represented, the decay of the rotation speed of the eccentric axis 6 along the rotation cycle may be achieved through the replacement of the elastic component of the elastic cord 3,

12 by a torque limiting device.
In another development of the invention not represented, the electrical source 9 may be replaced by an accumulator or a transformer, which may be directly connected to the public electric light mains, or by both.
In another development of the invention, not represented, the electric motor 14, the speed reduction mechanism 11, 13, 15 and the eccentric axis 6 may be replaced by an electromagnetic coil or a wind up mechanism, transmitting the same movement to the elastic cord 3, 12.
Yet in another development of this invention, not represented, the elastic effect given by the elastic cord 3, 12 may also be achieved through the use of elastic transmission belts 13, or even through the use of a tensor element transverse to the transmission belt 13 acting on this latter with a spring effect. In these cases, the cord 3, 12 may consist only of an inelastic strap 3.
In a development of the invention not represented, the elastic cord 3, 12 consists of a belt or cord made of elastic elastomer (natural or synthetic).
In a possible development of the invention, not represented, the elastic cord, including its strap, may be replaced by a pneumatic cylinder with an adjustable fixation point, with spring effect (through the compression of the air inside) having simultaneously a shock absorbent effect.
In another possible development of this invention, not represented, it may be included in the elastic CORD 3, 12 a force/tension transducer that, as it detects a certain tension, emits an electrical signal to the speed regulator of the electric motor, which will automatically regulate the motor speed in such a way that the desired synchronism between the frequency of both inducer and induced movements is achieved.
Yet in another not represented development of the invention, the speed regulator 7 may be a rheostat, a potentiometer or

13 any other electric motor speed regulation device (electronic, for instance).
In another development of this invention, the rocking mechanism 4 may work suspended from the carrying handle 2 or from any other equivalent fixation point on the baby chair 1 by the elastic cord 3, 12 itself, being then necessary to adjust the relationship between the elastic characteristic of the cord 3, 12 and the own weight of the rocking mechanism 4.
The rocking mechanism 4 can work with the type of baby chair 1 used in this description, but can also be adapted to work with a chair suspended from a frame, as well as with bouncers, bouncing chairs or any other type of devices to which a pendulum or oscillatory movement can be impaired, that may be suitable for baby use or for any other use.
It may be foreseen, apart or coupled to the rocking device, a chair boundary guide consisting of two L-shaped profiles, of adequate height, connected by bars or by a plane platform of synthetic material (plastic) longitudinally limited by two small wall perpendicular to the upper surface of said platform, in such a way as to avoid the baby chair to leave its alignment relative to the rocking chair.
The said boundary guide may even be used as a chair support platform, allowing a smooth movement even when it is used on irregular or rough surfaces.

Claims

1 - Rocking device, which allows the induction of an oscillatory swing movement to a baby chair or support device (1) and to the baby placed on it, which has a curved base or has a sufficiently elastic structure that allows the baby to be rocked, said movement being achieved through the action of a cord (3, 12), with a reciprocate movement, said rocking device consisting of an actuation mechanism (4) comprising an actuator mechanism (6, 7, 9, 11, 13, 14, 15) which impairs a reciprocate movement to a first end of said cord (3, 12) which transmits the reciprocate movement, through its other end, to a carrying handle or any other equivalent fixation point (2) of a baby chair or child support or transport device (1), characterized in that said cord (3, 12) is an elastic cord which, during the movement, adjusts itself and absorbs the varying distances between its end fixation points, being these varying distances caused by the instantaneous phase differences between the movement of the eccentric axis (6) and the said fixation point (2), said elastic cord (3, 12) transmitting a vertical oscillating force downwards which induces the displacement of said fixation point (2) and impairing a rocking movement to the baby chair or child support or transport device (1), the rocking device being capable of adjusting the frequency of the inducer movement to the natural frequency of the movement induced in the baby chair or child support or transport device (1) with the baby, through the natural decay of the motor speed that occurs when it is loaded with a force applied by the elastic cord (3, 12), the period of the movement of the baby chair (1) being equalized by period of the movement of the rocking device.

2 - The rocking device of claim 1 wherein the actuator mechanism (4) is coupled to said baby chair or support device (1) and the loop of the elastic cord (3, 12) is fixed to a fixation point (17) external to said chair or device (1).

3 - The rocking device of claim 1 or 2, wherein the actuator mechanism (11, 13, 14, 15) includes a motor (14), a speed reduction mechanism ((11, 13, 15), an eccentric axis (6) fixed in a regulation slot (10) of pulley (11).

4 - The rocking device of claim 1, 2 or 3, wherein said motor (14) is an electric motor powered by a power source (9) which consists of an accumulator and/or a transformer.

- The rocking device of claim 4, wherein the power source (9) consists of power batteries.

6 - The rocking device of claim 4, wherein said power source consists of a power accumulator or of a transformer which may be directly connected to the public electric light mains, or of both.
7 - The rocking device of claim 4, wherein the end of said elastic cord (3, 12) opposed to said actuator mechanism (6,

7, 9, 11, 13, 14, 15), forms a strap loop which allows the adjustment to the height of the carrying handle (2) or of any other alternative fixation point of said baby chair or support device (1) or even to a fixation point external to said chair or support device (1), when the said rocking device is coupled to said chair or support device(1).

8 - The rocking device of claim 1, wherein the actuator mechanism (4) is suspended from the carrying handle (2) or from any other equivalent fixation point of the baby chair (1) by the elastic cord (3, 12).

9 - The rocking device of claim 2, wherein the external fixation point is a weight suspended from the rocking device (4) by the elastic cord (3, 12).

16A

- The rocking device of claim 1 or 2, wherein said motor (14) is an electromagnetic coil that transmits to said elastic cord (3, 12) a reciprocate movement.

11 - The rocking device of claim 1 or 2, wherein said motor (14) is a wind up device that transmits to said elastic cord (3, 12) a reciprocate movement.

12 - The rocking device of claim 1 or 2, wherein said elastic cord (3, 12) is an elastic transmission belt or is an association of a belt (13) with a tensor element transverse to the transmission belt (13) acting on this latter with a spring effect, being the transmission of the movement to said chair or device (1) exclusively done by means of an inelastic strap (3).

13 - The rocking device of claim 1 or 2, wherein said elastic cord is an elastic cord made of natural or synthetic elastomer (3).

14 - The rocking device of claim 2 or 2, wherein said elastic cord is a pneumatic cylinder with an adjustable fixation device, with simultaneous spring and shock absorbing effects.

- The rocking device of claim 1 or 2, wherein the elastic element (12) of said elastic cord (3, 12) is a torque limiting device.

16 - The rocking device of claim 1, 2, 12, 13, 14, or 15, wherein a force/tension transducer is included in said elastic cord setup.

17 - The rocking device of claim 1 or 2, wherein the speed regulator (7) is a rheostat, a potentiometer or an electronic speed regulation device.

18 - The rocking device of claim 1 or 2, wherein a chair boundary guide is included to limit sideways the movement of said chair or device (1) consisting of two parallel L-shaped profiles held together by several transversal bars or by a plane platform of synthetic material (plastic) longitudinally limited by two small wall perpendicular to the upper surface of said platform, which is used as base platform for said chair or device (1).

19 - The rocking device of claim 1 or 2, wherein said actuator device includes additionally to said speed regulator (7) and said power source (9) a motor (14) and a pulley (11), being said motor directly coupled to said pulley (11).

20 - The rocking device of claim 1 or 2, wherein said elastic cord (3, 12) is a spring.