SE540973C2

SE540973C2 - Baby stroller brake system

Info

Publication number: SE540973C2
Application number: SE1750621A
Authority: SE
Inventors: Henrik Bie
Original assignee: Carl Philippe Ab C/O Ericsson
Priority date: 2017-05-18
Filing date: 2017-05-18
Publication date: 2019-02-12
Also published as: SE1750621A1; WO2018212694A1

Abstract

A baby stroller brake system (2) comprising a sensor unit (4), a control unit (6), and a brake unit (8). The sensor unit (4) is structured to be mounted on a baby stroller (10), and comprises at least one sensor (12) configured to detect an object (14) present within a three-dimensional detection space (16).The control unit (6) comprises a processor (20), a memory (22), and a movement detecting device (24) capable of determining a velocity V of said baby stroller (10). The processor (20) is configured to continuously receive determined velocity values from said movement detecting device (24) and detection information of a sensor signal (18). Brake control rules comprises determining a brake activation delay Δ in dependence of the present velocity V of the baby stroller, wherein the brake activation delay Δ is a time period from a point of time when no object is detected within the detection space (16) until a brake instruction is generated in order to brake the baby stroller, and wherein said brake activation delay Δ is varied in dependence of said velocity V.

Description

Baby stroller brake system Technical field The present disclosure relates to a baby stroller brake system, and in particular to a modular baby stroller brake system provided with an improved brake system taken various aspects into account when activating and deactivating the brake of the baby stroller.

Background Baby strollers, prams, pushchairs, baby buggies, baby carriages or the like are known as wheeled vehicles used for transporting children of varying sizes in seated and/or reclined positions. These are conventionally equipped with a brake system which is manually engaged by for example a foot pedal or a hand operated switch. Most of the currently available prams or the like use manual brake systems of this type. A safety problem may arise if the driver accidentally forgets to engage the brake system. Accidents have occurred where prams or the like carrying a child have rolled out into road cross-sections or train tracks because the driver has forgotten to engage the brakes. In recent years, prams having rotatable or swiveling front wheels have gained in popularity. Having such swiveling front wheels increases the risk of such accidents since the prams or the like may rotate towards slopes and start to move down the slope if left unattended with the brakes disengaged. To avoid accidents of this type, various solutions for automatic brake systems have been proposed where the brake is automatically engaged when the pram or the like is left unattended.

In the following some prior art solutions will be briefly discussed.

US-2007/0051566 relates to a pram or a stroller provided with an electricallyoperated brake apparatus which is applied automatically on a user releasing their grip from a handle. The braking does not occur immediately if grip or touch sensors arranged on the handle register that the user has released the handle. A programmable controller is provided which only applies brake if sensors detect movement of the pram and/or that the pram has moved more than a set distance subsequent to release of handle. The braking apparatus acts as a safety feature that only applies if a pram is released on a slope and movement due to the slope is detected. A processing unit is provided that determines the velocity of the pram by sensing speed of rotation of the wheels. If the velocity is beyond a certain value and if it is determined from the touch pad arranged at the handle that the pram is not grasped, the brake is activated in order to stop movement of the pram.

US-2009/0120736 relates to a manually controlled wheeled vehicle whose wheels are locked by a braking mechanism. A proximity sensing mechanism is provided that determines when an operator is sufficiently in control of the wheeled vehicle. Upon an operator presence being determined, the proximity sensor calls for the release of the wheel locks and/or braking mechanisms. Once the operator is no longer in the proper position, the wheel locks or brakes re-engage.

The proximity sensor may be embodied by an electric field sensing mechanism, an infrared interrupt sensor, or a radio frequency module to sense the presence of an operator who holds a radio frequency key.

US-8991838 relates to a stroller frame with an automatic brake mechanism that may be actuated by using a hand detecting handle. The handle is capable of detecting a user’s hand by a change of capacitance on its surface. Braking members are provided structured to lock and unlock the wheels in dependence of user hand detection.

JP5442899 (B1 ) relates to a safety system for a baby carriage or a nursing vehicle provided with a brake device, and more particularly to a safety system for detecting a surrounding situation and controlling a braking device of a baby carriage or a nursing vehicle. A human detecting unit is arranged constituted by an RF transmitter to be carried with the user and an RF receiver provided at the baby carriage. The strength of the radio wave received by the RF receiver is applied for judging the presence or absence of the user.

In a further example an inclination value is determined based upon position information from a GPS receiver, and this information is applied when activating the brake device.

The object of the present invention is to achieve an improved baby stroller brake system, where the improvement lies in a capability to adapt the braking activities to various situations that may occur during normal use of the baby stroller.

Summary The above-mentioned object is achieved by the present invention according to the independent claims.

Preferred embodiments are set forth in the dependent claims.

According to a first aspect of the present invention a baby stroller brake system is provided that comprises a sensor unit, a control unit, and a brake unit.

The sensor unit is structured to be mounted on a baby stroller, and comprises at least one sensor configured to detect an object present within a three-dimensional detection space, and that the sensor unit is configured to generate a sensor signal including detection information in dependence of the detections made by the at least one sensor.

The control unit comprises a processor, a memory, and a movement detecting device capable of determining a velocity V of said baby stroller, the control unit is configured to generate a brake control signal including brake instructions and to apply the brake control signal to the brake unit.

The brake unit comprises a brake member and a braking activation member, the brake member is configured to achieve braking or release of braking of the baby stroller, and the braking activation member is configured to control activation of the brake member in dependence of the brake control signal.

The processor is configured to continuously receive determined velocity values from said movement detecting device and detection information of said sensor signal, and to apply a set of brake control rules for braking and release of braking of the baby stroller, the brake control rules comprises determining a brake activation delay ? in dependence of the present velocity V of the baby stroller, wherein the brake activation delay ? is a time period from a point of time when no object is detected within the detection space until a brake instruction is generated in order to brake the baby stroller, and wherein said brake activation delay ? is varied in dependence of said velocity V.

According to one embodiment the brake activation delay ? is varied in dependence of the velocity V such that the brake activation delay ? decreases with increasing velocity. Thereby an intelligent braking of the baby stroller is achieved, which is advantageous, as it adapts to various scenarios.

According to another embodiment the brake rule includes that no braking is performed when the velocity is 0. This is beneficial, as no braking is required when the baby stroller already stands still.

In still another embodiment the brake rule includes that for velocities equal or higher than a preset velocity value in the range of 3-6 km/h, the activation delay is a constant value in the interval 1 - 2.5 seconds. This is advantageous as braking needs to be made soon as the velocity is quite high.

In still another embodiment an equation for determining the activation is applied. For a velocity V in the interval 0 < V < 4, the activation delay ? is determined according to the equation ? = - k x V a constant, where k is in the interval of 0.5 to 2 and the constant is in the interval of 3 to 8, for v = 0 the brake is released, and for velocities equal or higher than 4 km/h the delay is a preset value in the interval of 1 - 2 seconds, preferably 1.5 seconds.

In a further embodiment the brake system is a modular brake system where the sensor unit, the control unit and the brake unit are separate physical entities. Thereby, these units may be mounted at a baby stroller.

According to another embodiment the detection space when seen from above is delimited by two detection limit lines extending from the sensor unit and separated by an angle in the range of at least 120 degrees, and preferably approximately 180 degrees. Thereby, an operator may be detected even if he/she is walking or running beside the baby stroller. Furthermore, the detection space comprises a maximum detection distance in the interval of 0.75 - 1.5 meter.

In still another embodiment the movement detecting device is a GPS-unit. The control unit is preferably provided with similar functionality as a smartphone, where often a GPS-unit is included.

According to a second aspect, the present invention relates to a baby stroller brake system that comprises a sensor unit, a control unit, and a brake unit.

The sensor unit is structured to be mounted on a baby stroller , and comprises at least one sensor configured to detect an object present within a three-dimensional detection space, and that the sensor unit is configured to generate a sensor signal including detection information in dependence of the detections made by the at least one sensor.

The control unit comprises a processor and a memory, and the control unit is configured to generate a brake control signal including brake instructions and to apply the brake control signal to the brake unit.

The brake unit comprises a brake member and a braking activation member, and is configured to achieve braking or release of braking of the baby stroller. The braking activation member is configured to control activation of the brake member in dependence of the brake control signal.

The processor is configured to continuously receive detection information of the sensor signal, and to apply a set of brake control rules for braking and release of braking of the baby stroller, the brake control rules comprises determining a brake activation delay ?, which is a time period from a point of time when no object is detected within the detection space until a brake instruction is generated in order to brake the baby stroller. The brake activation delay ? is a fixed predetermined value. The fixed predetermined value is greater than 0 and is set in advance in dependence on e.g. the type of baby stroller, the type of brake and how the baby stroller is used.

When using a baby stroller provided with the baby stroller brake system according to the present invention it is not necessary that the user holds the handle, but he/she must be in the vicinity, i.e. in the detection space, in order to have the brake released.

Brief description of the drawings Figure 1 is a schematic illustration of a baby stroller provided with a baby stroller brake system according to the present invention.

Figure 2 is a view from above of a handle of a baby stroller where a sensor unit according to the present invention is mounted.

Figure 3 is a block diagram schematically illustrating the baby stroller brake system according to the present invention.

Figure 4 is a diagram illustrating the relationship between the velocity and the brake activation delay, according to one embodiment.

Figure 5 is a diagram illustrating the relationship between the velocity and the brake activation delay, according to another embodiment.

Figure 6 is a block diagram schematically illustrating the baby stroller brake system according to another variation of the present invention.

Detailed description The baby stroller brake system will now be described in detail with references to the appended figures. Throughout the figures the same, or similar, items have the same reference signs. Moreover, the items and the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention.

The invention relates to a baby stroller brake system 2 comprising a sensor unit 4, a control unit 6, and a brake unit 8.

In the schematic illustration shown in figure 1 a baby stroller 10 is disclosed provided with a baby stroller brake system. In the illustrated baby stroller the sensor unit 4 is mounted at the handle of the baby stroller such that an object 14, e.g. an operator, in a detection space 16 may be detected.

It will now also be referred to the schematic block diagram shown in figure 3 of the baby stroller brake system.

The sensor unit 4 comprises at least one sensor 12 configured to detect an object 14 present within the three-dimensional detection space 16. The detection space extends in a direction where an operator is present during normal use of the baby stroller. The sensor unit is structured to be mounted such that a person may be detected that is in a position for handling, i.e. pushing or pulling, the baby stroller. The sensor unit may e.g. be mounted at a handle, and is provided with a mounting member, e.g. a strap or similar, that facilitates easy mounting of the sensor unit. The sensor unit does not need to be mounted at the handle but may be mounted at any position of the baby stroller where a person may be detected. That may e.g. be at the frame of the stroller.

The sensor unit 4 is configured to generate a sensor signal 18 including detection information in dependence of the detections made by the at least one sensor 12. Various different types of sensors may be applied. According to different embodiments the sensor is one or many of an infrared sensor, an ultrasonic sensor, or a capacitive sensor. An important requirement of the sensor is that it should have the capability to detect objects within the entire detection space. Preferably, the detection space 16, when seen from above is defined by two detection limit lines 32 (see figure 2) extending from the sensor unit 4 and separated by an angle in the range of at least 120 degrees, and preferably approximately 180 degrees. In addition the detection space comprises a maximum detection distance in the interval of 0.75 - 1.5 meters. The distance is determined as the largest distance to the baby stroller where an operator may be present and still have control of the baby stroller.

One type of sensors that is applicable herein is so-called proximity sensors. A proximity sensor is a sensor able to detect the presence of nearby objects without any physical contact.

A proximity sensor often emits an electromagnetic field or a beam of electromagnetic radiation (infrared, for instance), and looks for changes in the field or return signal. The object being sensed is often referred to as the proximity sensor's target. Different proximity sensor targets demand different sensors. For example, a capacitive or photoelectric sensor might be suitable for a plastic target; an inductive proximity sensor always requires a metal target. The maximum distance that this sensor can detect is defined "nominal range". Some sensors have adjustments of the nominal range or means to report a graduated detection distance. Proximity sensors can have a high reliability and long functional life because of the absence of mechanical parts and lack of physical contact between sensor and the sensed object.

The control unit 6 comprises a processor 20, a memory 22, and a movement detecting device 24 capable of determining a velocity V of the baby stroller 10.

The control unit may have a functionality similar to that of a smartphone, e.g. being provided with a chargeable battery and a movement detecting device, e.g. a GPS-unit, which may determine the velocity.

As an alternative the movement detecting device may determine the velocity by analyzing a charging current received by a current generator arranged in relation to the wheels of the baby stroller. Still other variations of the movement detecting device exist, e.g. by detecting the number of rotations of the wheels per time unit the velocity may be determined.

The control unit 6 is configured to generate a brake control signal 26 including brake instructions and to apply the brake control signal 26 to the brake unit 8.

The brake unit 8 comprises a brake member 28 and a braking activation member 30. The brake member 28 is configured to achieve braking or release of braking of the baby stroller 10, and may be a brake originally mounted on the baby stroller or may be a separate and/or additional brake that is structured to be mounted on the stroller. Various types of brake members exist. As an example the brake member has a pin-structure that is moved such that it mechanically prevents rotation of the wheel(s) of the baby stroller. Another example is a brake that is moved into contact with the tyres of the wheel(s) and thereby brakes the baby stroller.

The braking activation member 30 is configured to control activation of the brake member 28 in dependence of the brake control signal 26. Thus, the braking activation member transfers the brake instruction in the brake control signal to braking activity, e.g. by generating movement of a wire physically attached to the brake member in order to brake or release braking. The brake activation member may be a solenoid having a wire attached to its moveable part. The braking action is illustrated by the vertical arrow from brake member 28.

Preferably, the brake activation member 30 is also configured to detect any manual release of the brake member 28, and in that case apply a reset signal to the control unit 6 in order to set the control unit in non-braking state. This is illustrated by the double arrow of the control signal 26. As an alternative, or in addition, the control unit is configured to receive a reset input command from the user, e.g. via a button or similar, resulting in the control unit is set in the nonbraking state.

The processor 20 in the control unit 6 is configured to continuously receive the determined velocity values from the movement detecting device 24 and detection information of the sensor signal 18. A set of brake control rules for braking and release of braking of the baby stroller is stored in the memory 22, and the processor is configured to apply the set of brake control rules. The brake control rules comprise determining a brake activation delay ? in dependence of the present velocity V of the baby stroller. The brake activation delay ? is a time period from a point of time when no object is detected within the detection space 16 until a brake instruction is generated in order to brake the baby stroller. The brake activation delay ? is varied in dependence of the velocity V.

Generally, the brake activation delay ? is varied in dependence of the velocity V such that the brake activation delay ? decreases with increasing velocity. In other words, if the baby stroller only moves slowly then it is not necessary to brake the stroller immediately as the distance it rolls is not very long. On the other side, if it moves faster it is important to brake the stroller at an earlier instant.

When the baby stroller does not move, i.e. the velocity is 0, it is not necessary to perform any braking, and therefore a brake rule is preferably applied that includes that no braking is performed when the velocity is 0.

According to another embodiment a brake rule includes that, for velocities equal or higher than a preset velocity value in the range of 3-6 km/h, e.g. 4 km/h, the activation delay is a constant value in the interval 1 - 2.5 seconds, e.g. 1.5 seconds.

According to still another embodiment an equation is applied to determine the activation delay in dependence of the velocity.

The equation is applicable for velocities V within the interval 0 < V < 4. The activation delay ? is then determined according to an equation ? = - k x V a constant, where k is in the interval of 0.5 to 2 and the constant is in the interval of 3 to 8.

In the graph in figure 4 one example of the equation is illustrated. The illustrated equation is ? = - V 4.5, i.e. k is 1 and the constant is 4.5.

In the graph in figure 4 another example is illustrated. In this example the activation delay is step-wise constant. For velocities higher than 0, but below 1 km/h the delay is 4 seconds; for velocities between 1 and 2 km/h the delay is 3 seconds; for velocities between 3 and 4 km/h the delay is 2 seconds, and for velocities higher than 4 km/h the delay is 1.5 seconds.

Note that the graph in figure 4 illustrates only an example, and the values may be varied depending on the particular set-up of the system, e.g. which type of baby stroller is used.

According to one embodiment the brake system is a modular brake system where the sensor unit 4, the control unit 6 and the brake unit 8 are separate physical entities. This is advantageous in that the system may then be mounted on an already existing baby stroller. The different parts of the system are then provided with various mounting members in order to mount them at suitable positions of the baby stroller. For example, the sensor unit is provided with a mounting member structured to mount the sensor unit at the handle of the baby stroller.

A power source is provided in order to energize the sensor unit, the control unit and the brake unit. The power source may be included in the control unit and electrical cables are then provided and connected to the other units. The power source may be a rechargeable battery. As an alternative, a generator may be mounted in connection with the wheels of the baby stroller such that energy may be generated when the baby stroller moves.

The various signals between the sensor unit, the control unit and the brake unit may be transferred via signal cables, or may be transferred wirelessly.

In a further variation of the baby stroller brake system the sensor unit comprises a first sensor capable of detecting objects in a near field part of the detection space, and a second sensor capable of detecting objects in a far field part of the detection space.

As an example the near field part is a distance closer than 2 cm and the far field part is equal or greater than 2 cm from the first and second sensors, respectively. Further brake control rules may then be provided that will take the presence or non-presence of objects within both the near field part, and the far field part of the detection space into account when determining the activation delay.

With references to the schematic block diagram shown in figure 5 a further variation of the baby stroller brake system according to present invention will be disclosed. In this variation no movement detecting device is included, i.e. no velocity needs to be measured. Instead the brake activation delay ? is set to a fixed predetermined value. This value may be set by the user and may depend upon the type of the baby stroller, the type of brakes and/or how the baby user is used.

Thus, a baby stroller brake system 2 comprising a sensor unit 4, a control unit (6), and a brake unit 8 is provided.

The sensor unit 4 is structured to be mounted on a baby stroller 10, and comprises at least one sensor 12 configured to detect an object 14 present within a three-dimensional detection space 16, and that the sensor unit 4 is configured to generate a sensor signal 18 including detection information in dependence of the detections made by the at least one sensor 12. The type of sensor may the same as discussed above.

The control unit 6 comprises a processor 20 and a memory 22. The control unit 6 is configured to generate a brake control signal 26 including brake instructions and to apply the brake control signal 26 to the brake unit 8.

The brake unit 8 comprises a brake member 28 and a braking activation member 30, the brake member 28 is configured to achieve braking or release of braking of the baby stroller 10. The braking activation member 30 is configured to control activation of the brake member 28 in dependence of the brake control signal 26. The processor 20 is configured to continuously receive detection information of the sensor signal 18, and to apply a set of brake control rules for braking and release of braking of the baby stroller. The brake control rules comprises determining a brake activation delay ?, wherein the brake activation delay ? is a time period from a point of time when no object is detected within the detection space 16 until a brake instruction is generated in order to brake the baby stroller, and wherein said brake activation delay ? is a fixed predetermined value. The predetermined value is greater than 0, and may be set by the user.

It should be noted that all relevant features described above in relation with the baby stroller brake system provided with the movement detecting device to measure the velocity is equally applicable to the variation where no velocity is measured.

The present invention is not limited to the above-described preferred embodiments. Various alternatives, modifications and equivalents may be used. Therefore, the above embodiments should not be taken as limiting the scope of the invention, which is defined by the appending claims.

Claims

1. A baby stroller brake system (2) comprising a sensor unit (4), a control unit (6), and a brake unit (8), - the sensor unit (4) is structured to be mounted on a baby stroller (10), and comprises at least one sensor (12) configured to detect an object (14) present within a three-dimensional detection space (16), and that the sensor unit (4) is configured to generate a sensor signal (18) including detection information in dependence of the detections made by the at least one sensor (12), - the control unit (6) comprises a processor (20), a memory (22), and a movement detecting device (24) capable of determining a velocity V of said baby stroller (10), the control unit (6) is configured to generate a brake control signal (26) including brake instructions and to apply the brake control signal (26) to the brake unit (8), - the brake unit (8) comprises a brake member (28) and a braking activation member (30), the brake member (28) is configured to achieve braking or release of braking of the baby stroller (10), and said braking activation member (30) is configured to control activation of the brake member (28) in dependence of said brake control signal (26), characterized in that said processor (20) is configured to continuously receive determined velocity values from said movement detecting device (24) and detection information of said sensor signal (18), and to apply a set of brake control rules for braking and release of braking of the baby stroller, the brake control rules comprises determining a brake activation delay ? in dependence of the present velocity V of the baby stroller, wherein the brake activation delay ? is a time period from a point of time when no object is detected within the detection space (16) until a brake instruction is generated in order to brake the baby stroller, and wherein said brake activation delay ? is varied in dependence of said velocity V.

2. The baby stroller brake system (2) according to claim 1, wherein said brake activation delay ? is varied in dependence of said velocity V such that the brake activation delay ? decreases with increasing velocity.

3. The baby stroller brake system (2) according to claim 1 or 2, wherein said brake rule includes that no braking is performed when the velocity is 0.

4. The baby stroller brake system (2) according to any of claims 1-3, wherein said brake rule includes that for velocities equal or higher than a preset velocity value in the range of 3-6 km/h, the activation delay is a constant value in the interval 1 - 2.5 seconds.

5. The baby stroller brake system (2) according to any of claims 1-4, wherein, for a velocity V in the interval 0 < V < 4, the activation delay ? is determined according to an equation ? = - k x V a constant, where k is in the interval of 0.5 to 2 and the constant is in the interval of 3 to 8, for v = 0 the brake is released, and for velocities equal or higher than 4 km/h the delay is a preset value in the interval of 1 - 2 seconds, preferably 1.5 seconds.

6. The baby stroller brake system (2) according to any of claims 1 -5, wherein brake system is a modular brake system where the sensor unit (4), the control unit (6) and the brake unit (8) are separate physical entities.

7. The baby stroller brake system (2) according to any of claims 1-6, wherein said detection space (16) when seen from above is delimited by two detection limit lines (32) extending from the sensor unit (4) and separated by an angle in the range of at least 120 degrees, and preferably approximately 180 degrees, and wherein said detection space comprises a maximum detection distance in the interval of 0.75 - 1.5 metre.

8. The baby stroller brake system (2) according to any of claims 1 -7, wherein said sensor is one or many of an infrared sensor, an ultrasonic sensor, or a capacitive sensor.

9. The baby stroller brake system (2) according to any of claims 1 -8, wherein said movement detecting device is a GPS-unit.

10. A baby stroller brake system (2) comprising a sensor unit (4), a control unit (6), and a brake unit (8), - the sensor unit (4) is structured to be mounted on a baby stroller (10), and comprises at least one sensor (12) configured to detect an object (14) present within a three-dimensional detection space (16), and that the sensor unit (4) is configured to generate a sensor signal (18) including detection information in dependence of the detections made by the at least one sensor (12), - the control unit (6) comprises a processor (20) and a memory (22), the control unit (6) is configured to generate a brake control signal (26) including brake instructions and to apply the brake control signal (26) to the brake unit (8), - the brake unit (8) comprises a brake member (28) and a braking activation member (30), the brake member (28) is configured to achieve braking or release of braking of the baby stroller (10), and said braking activation member (30) is configured to control activation of the brake member (28) in dependence of said brake control signal (26), characterized in that said processor (20) is configured to continuously receive detection information of said sensor signal (18), and to apply a set of brake control rules for braking and release of braking of the baby stroller, the brake control rules comprises determining a brake activation delay ?, wherein the brake activation delay ? is a time period from a point of time when no object is detected within the detection space (16) until a brake instruction is generated in order to brake the baby stroller, and wherein said brake activation delay ? is a fixed predetermined value.