GB2590925A

GB2590925A - Power pram

Info

Publication number: GB2590925A
Application number: GB2000122.8A
Authority: GB
Inventors: Jeffrey Taylor Philip
Original assignee: Silver Cross IP Ltd
Current assignee: Silver Cross IP Ltd
Priority date: 2020-01-06
Filing date: 2020-01-06
Publication date: 2021-07-14
Anticipated expiration: 2040-01-06
Also published as: GB2590925B; GB202000122D0; CN114829228A; WO2021140320A1

Abstract

A unitary motor and power module 100 for a pram comprising: a housing containing (110, see fig.1): an electric motor, and a battery electrically coupled to the motor. A drive shaft 125 is located at respective ends of the housing configured such that, when the housing is placed between a pair of pram wheels along a common rotational axis of the wheels, the drive shafts engage with the respective wheels and are operable to transmit rotational force from the electric motor to the wheels. The housing may comprise means of engaging with the frame of the pram either with a recess or protuberance. The drive shafts may be splined and may have a frustoconical terminal. In addition, the battery may be a lithium ion battery and the motor may be brushed or brushless. Said motor may be used as a dynamo to power the battery and said battery may power lights, speakers, heaters.

Description

Power Pram The present invention relates to a unitary motor and power module for a pram and a powered pram comprising said unitary motor and power module.

Background

Prams (also known as strollers, buggies and push chairs) using electric motors to provide rotational force to the wheels, thereby making the pram easier for the operator to push, are known. It is also known to make a battery detachable from the pram so that it may be charged separately. GB 2563573 A is an example of such a pram.

However, such prams lack flexibility as, although the battery may be removed, the motor remains attached to the pram and, in the absence of the battery to provide power to it, simply provides unwanted excess weight.

It is the objective of the present invention to address at least one of the aforementioned problems.

Summary of the Invention

A first aspect of the present invention is a unitary motor and power module for a pram comprising: a housing containing: an electric motor, and a battery electrically coupled to the motor; and a drive shaft located at respective ends of the housing configured such that, when the housing is placed between a pair of pram wheels along a common rotational axis of the wheels, the drive shafts engage with the respective wheels and are operable to transmit rotational force from the electric motor to the wheels. The unitary nature of the motor and power module allows for the entire module to be attached to the pram when additional power is needed and for the entire module to be removed when additional power is not needed. This saves significantly on weight when the motor is not required, making the pram easier to move. It will be appreciated that one drive shaft may be provided for each electric motor. In certain configurations, there are two electric motors and so there are two drive shafts. A single driveshaft which extends between opposing ends of the module may be provided. In addition, keeping the motor and battery in a single unit also protects them from the external environment when the module is in use and when it is removed from the pram. The unitary nature of the module also allows for easy customisation of products (e.g. with different ratings of motor and/or battery) for the manufacturer, seller and user. In addition, the provision of a unitary battery and motor unit allows for a modular system in which a selection of prams of different functionality may be provided. For example, it allows for the provision of prams which do not include any powered assistance, prams which include a wiring loom within the frame and having a plurality of electrical connection points to which electronic accessories may be attached to a battery held in the same position as the unitary module of the present invention, or a pram including the unitary module of the present invention. Furthermore, it may be desirable to remove the motor and battery from the pram to avoid the motor and battery being kept in undesirable conditions, such as particularly hot or cold temperatures or in a damp environment, for extended periods of time. Furthermore, the battery needs to be in electrical connection with the motor(s) which power the pram. As such, where the battery is removable, there needs to be an electrical connector which is able to be reversibly connected. This will generally be in the form of metal contacts, such as copper contacts. Since prams may be exposed to water and possibly even salt during the winter, the metal contacts may become corroded or otherwise damaged. As such, the electrical connection between the battery and the motor(s) may be adversely affected. By providing a unitary module, the connection between the battery and motor(s) may be less prone to such effects. It will of course be appreciated that the module may be configured to allow replacement of the battery and/or motor(s).

The housing may be provided with means to engage with a static part of the pram, such as the frame, when the housing is placed between the pair of pram wheels.

Engaging with a static part of the pram ensures that, when the motor applies rotational force to the wheels, it is the wheels that rotate in the direction of the motor, rather than the motor that rotates in the opposite direction. Any suitable anti-rotation means may be used. Static is to be understood as part of a pram which does not rotate when the pram is in motion. It will be appreciated that the static part of the pram may be moveable, such as when the pram is being folded, but is static to the extent that it is able to stop the module rotating when torque is provided by the motor(s).

The means may comprise a protuberance extending from the housing, the protuberance configured to co-operate with a recess in the static part of the pram.

Alternatively, or additionally, the means may comprise a recess in the housing (which may be located at an end of the housing), the recess configured to cooperate with a protuberance extending from the static part of the pram. Preferably, the recess(es) and/or protuberances are configured such that the unitary motor and power module may be installed between the coaxial wheels of the pram simply by sliding the module into place in a radial manner. Typically, in such embodiments the recess includes a channel connecting radially to the outer diameter through which a protuberance may be passed. It will be appreciated that the apparatus may be configured such that the unitary motor and power module may be installed in an axial manner. In any embodiment, the housing of the unitary motor and power module may be shaped such that it may be engaged with a pram in a specific orientation. The housing may include a flattened portion which is shaped to engage with a corresponding flattened portion on a pram. The flattened portions may serve to prevent relative rotation of the unitary motor and power module and a pram with which it is engaged.

The or each drive shaft may be splined. The presence of splines on the drive shaft permits the shaft to mechanically interlock with a corresponding socket on, or coupled to, the wheel. This provides for the transfer of rotational force from the motor to the wheels. Any suitable number of splines may be used. Alternatively, rather than splines, the drive shaft may simply have a cross section that prevents rotation of the shaft relative to the wheel once it is fitted into the corresponding socket. For example, the end of the shaft may have a non-circular cross-section. By having a non-circular cross section, such as a square cross-section, the shaft may engage with a corresponding receiving portion, such as a socket, of a pram and allow the shaft to power the wheels of the pram.

Each drive shaft may be moveable from an extended position, which may be proud of the surface of the end of housing, to a retracted position flush with or axially inwards of the surface of the end of the housing. Retraction of the drive shaft allows the unitary motor and power unit to be easily installed and removed from between the pram wheels, while the extended position ensures good mechanical contact with the socket on, or coupled to, the wheels and an efficiency transfer of rotational force.

The terminus of the or each drive shaft may be frustoconical. The drive shaft being narrower at the tip makes it easier to align the drive shaft with the corresponding socket on, or coupled to, the wheels. Substantially any shape that is narrowest at its terminus may exhibit this benefit (e.g. shapes from a full cone to a prism with a chamfered edge). The terminus of the or each drive shaft may be chamfered to allow easy engagement with the pram.

The electric motor may be operable to provide rotational force when one or both drive shafts are turned. In other words, the motor is triggered to rotate in sympathy to an externally applied rotational force. Such a motor acts as a 'power assist', reducing the effort expended by the operator to push the pram on which the unitary motor and power module is fitted. This is particularly beneficial when, for example, pushing the pram up an incline. As such, the apparatus may comprise a control module which is configurable to selectively provide power to the motor in response to detected inputs. The apparatus may include one or more sensors to detect movement of the pram. The sensors may be connected to a control module. The control module may be configurable to provide adjustable degrees of assistance from the motor(s).

The unitary motor and power module may further comprise at least one of a rotation sensor and a torque sensor. Each of these sensors is able to detect the imparting of rotational force to the drive shaft and/or wheel by sensing movement of these parts and detecting the application of force to them respecfively.

A portion of the surface of the or each drive shaft may comprise an electric contact electrically coupled to the battery. A portion of the surface of the or each end of the housing may comprise an electric contact electrically coupled to the battery. The provision of an external electrical contact permits charging of the unitary motor and power module. As such, the unitary module may include a charging port via which the battery may be charged. The invention is not particularly limited to the way in which the battery may be charged. For example, the battery may be charged via connection to a mains power supply, which may include a transformer to alter the voltage and/or current provided to the battery depending on the requirements of the battery. The battery may be charged via a USB cable or similar. In embodiments where the pram has additional circuitry, these contact points may provide suitable means for the provision of electrical power to these circuits from the battery. The electrical connection from the battery to any wiring within the frame of the pram may be provided by an electrical contact located on the unitary motor and battery module, and an electrical contact located on the frame.

Any suitable battery may be used. The battery may be a lithium ion battery. Lithium ion batteries are able to provide good performance for portable, rechargeable battery applications.

The electric motor may be a brushed or a brushless electric motor.

The motor may be operable to act as a dynamo. When the motor is not in use, it may be beneficial to have rotation of the drive shaft generate electrical power, which may be used to recharge the battery. Such 'regenerative braking' would be particularly beneficial when descending inclines. The motor may therefore be configured to provide a braking force to the wheels. There may be a clutch which disconnects the wheels from the electric motor(s) to allow free rotation of the wheels.

There may be provided at least two electric motors. The unitary module may comprise a shaft at each end which is configured to be rotated by an electric motor. By having separately driven drive shafts, the motors are able to rotate at different rates. This may be advantageous to allow improved steering of a pram. In addition, the unitary module may be configured to adjust the power provided to each electric motor in order to adjust the power provided at each drive shaft. This may be advantageous in steering a pram.

A second aspect of the present invention is a powered pram comprising a unitary motor and power module according to the first aspect of the present invention. The pram is configured to accept the unitary motor and power module between a coaxial set of wheels (e.g. the rear wheels). Being configured to accept the unitary motor and power module may comprise at least one of one or more sockets on, or coupled to, the wheels that are configured to accept the drive shaft (i.e. being complementary in shape) and a static part comprising a recess or protuberance that is complementary to the protuberance or recess of the housing.

The powered pram may further comprise wiring passed through the frame of the pram to connect electrical devices to the battery when the housing is placed between the pair of pram wheels. The electrical devices may include one or more of lights, speakers, heaters, solar panels, sockets, smart phones, fans, air filtration devices, video cameras, tablets, satellite navigation systems, charging stations, portable power devices, or any other device requiring electrical power. The provision of such wiring allows for further useful devices to be connected to the battery, for example lights to enable the operator to see their path clearly in low light conditions and to ensure that the pram is visible to others.

The powered pram may include control means for the electric motor. The control means may comprise a simple on/off switch to activate the motor, a throttle for the operator to select a particular speed, and/or a switch enabling a 'power assist' mode.

The control means may be operable to restrict the pram to a particular maximum speed and/or to prevent action of the motor in the absence of an operator (e.g. a dead man's switch located on the powered pram). Additionally, or alternatively, the control means may include a level sensor to enable the pram to work selectively depending on the incline of the pram (for example, engaging the motor when travelling uphill and disengaging the motor when travelling downhill).

Drawings Figure 1A shows a view of an embodiment of a unitary motor and power module according to the first aspect of the present invention with the drive shafts retracted.

Figure 1B shows the same embodiment as Figure 1A, with the drive shafts extended.

Figure 2A shows a perspective view of the rear wheels of a pram configured to receive the unitary motor and power module displayed in Figs 1A and 1B.

Figure 2B shows a perspective view of the pram of Fig 2A with the unitary motor and power module of Figs 1A and 1B.

Figure 2C shows a perspective view of a the pram of Fig 2A with the unitary motor and power module of Figs 1A and 1B fitted between the rear wheels.

Figure 3 shows a perspective view of an embodiment of the unitary motor and power module according to the first aspect of the present invention and the rear wheels of a pram configured to receive said unitary motor and power module.

Figure 4 shows a perspective view of the unitary motor and power module fitted on a charging station.

Figure 5A shows a rear view of a powered pram, with a unitary motor and power module fitted and wiring (indicated as dashed lines) passed through the frame.

Figure 5B shows a plan view of the powered pram of Figure 5A, with the unitary motor and power module fitted and wiring (indicated as dashed lines) passed through the frame.

Detailed Description

Figures 1A and 1B show one embodiment of the unitary motor and power module according to the first aspect of the present invention with the drive shafts in the retracted and extended positions respectively.

The housing 110 of the unitary motor and power module 100 contains the battery and motor (not shown) and is in the form of a cylinder with flared ends. Of course, substantially any shape that would connect the wheels of the pram to which the module is to be fitted would be suitable, on the proviso that it does not interfere with the operation of the pram. Typical shapes which may be employed for the housing 110 have a high aspect ratio, enabling bridging of the space between the wheels without risking contact with the group or the operator, such as cylinders, triangular prisms, cuboids, pentagonal prisms, hexagonal prisms and prisms of higher order polygons. The cylindrical portion of the housing 110 may be textured to make it easy to grip.

Alternative means may be used to improve grip, such as the addition of rubber material.

Each end 115 of the housing 110 includes a protuberance 120 which is shaped to fit into a complementary recess in the pram and will be described in more detail below.

In Fig 1A the drive shafts are retracted within the ends 115 of the housing 110. This prevents the drive shafts from catching on the wheel and/or frame of the pram as it is fitted.

In Fig. 1B the draft shafts 125 are in the extended position as they would be when fitted in a pram. The exposed parts of the drive shafts 125 are frustoconical, making it easier for the drive shafts 125 to be fitted into the corresponding sockets on, or connected to, the wheels. The drive shafts 125 are also splined to enhance their mechanical interaction with the sockets and the transfer of rotational force from the motor to the wheels by reducing the likelihood of slippage. It will be appreciated that the ability to extend or retract the ends of the drive shafts is optional.

The housing 110 of the embodiment shown in Figs. 1A and 1B includes the additional feature of a power (USB) socket 130 and a corresponding switch 135 for activating the socket. Of course, it will be understood that, while convenient, these components are not essential for the basic functions of the unitary motor and power module 100 and may be omitted.

Figure 2A shows the rear portion of a pram 200 configured to have the unitary motor and power module shown in Figs. 1A and 1B fitted between its rear wheels 210. The sockets to which the driveshafts of the unitary motor and power module are to interlock with and the recesses into which the protuberances of the housing are to slot are covered by caps 215. The caps 215 operate to prevent dirt entering or damage occurring to the sockets and/or recesses.

Figure 2B shows the unitary motor and power module 100 in the process of being fitted to the pram 200. The caps have been removed from the rear wheels 210 revealing the recesses 220 into which the protuberances 120 of the housing are to slot. In this embodiment, the static part of the pram in which the recesses are formed are the brackets that hold the wheels. Of course, the relationship between the recesses and protuberances may be reversed (i.e. the protuberances being on the static parts and the recesses being in the ends of the housing) or a complex interaction may be used. The design of the recesses and protuberances beneficially allows the unitary motor and power module 100 to simply be slid into position from above, with gravity holding the module in position. Removal of the caps has also revealed the sockets 225 into which the ends of the drive shafts 125 will fit. The splined nature of the drive shafts 125 has been reproduced in the sockets 225, ensuring a good fit and transferal of force when the motor is active. There may be means to positively attach the unitary module to the pram. Such means may be provided on one or both of the unitary module and the pram.

Figure 2C shows the unitary motor and power module 100 fitted between the rear wheels 210 of the pram 200. The driveshafts are mechanically intermeshed with the sockets (not shown) allowing transferral of rotational force from the motor to the wheels and the engagement of the protuberances on the ends of the housing with the recesses in the static part of the pram ensures that it is the wheels that are rotated rather than the housing.

Figure 3 shows an embodiment of a unitary motor and power module 300 and the rear portion of a pram 310 configured to have the unitary motor and power module 300 fitted between its rear wheels 320. In this embodiment the configuration of the recesses and protuberances has been reversed such that the recess 330 is in the end of the housing of the unitary motor and power module 300 and the protuberance 340 is located in the static portion of the pram On this case, the bracket holding the wheel). It should be noted that the drive shafts of the unitary motor and power module 300 are not shown in Figure 3.

Figure 4 shows the unitary motor and power module 300 placed on a charging station 400 which passes mains electricity to the unitary motor and power module 300 in order to charge the battery held within. The charging station includes a protuberance 410 configured to fit into recess 330 in one end of the unitary motor and power module 300. The charging station 400 is in electrical contact with the battery within the unitary motor and power module 300, this electrical contact is established through contacts of conductive material 420 in the protuberance 410 and corresponding contacts on a portion of the driveshaft. Alternatively, the contacts of the charging station may be located on a portion of the protuberance or top face of the charging station and the contacts of the unitary motor and power module 300 may be located on a portion of the recess of a portion of the end face of the housing. In a further alternative, the charging station charges the battery via induction. By using inductive charging, also known as wireless charging, it is possible to provide a sealed unit to prevent corrosion or damage to any exposed electrical contacts.

Figures 5A and 5B show a pram 500 fitted with a unitary motor and power module 510 and additionally comprising wiring throughout the frame (represented as dashed lines).

The battery of the unitary motor and power module 510 is in direct electrical contact with the wiring, with the contact being provided in the same manner as for between the charging station and the unitary motor and power module in Figure 4. The wiring is suitable to transmit electrical power from the battery to various points on the frame of the pram, such as the handle, the joints and the underslung basket. The points to which electrical power is transmitted may be in the form of sockets, such as USB sockets, operable to receive cables for the connection of devices such as tablet computers, smartphones, GPS, speakers, and lights. In particular, connections suitable for smartphones, such as USB sockets, are beneficial on the handle of the pram, freeing the hands of the operator when using the smartphone (e.g. when using a GPS application or making a phonecall). A lamp may be fitted on the front of the pram (e.g. on the front of the underslung basket) to provide illumination in low-light conditions and enhance visibility of the pram. Indeed, the wiring loom may be configured to provide power to any electronic device as required.

Claims

CLAIMS: A unitary motor and power module for a pram comprising: a housing containing: an electric motor, and a battery electrically coupled to the motor; and a drive shaft located at respective ends of the housing configured such that, when the housing is placed between a pair of pram wheels along a common rotational axis of the wheels, the drive shafts engage with the respective wheels and are operable to transmit rotational force from the electric motor to the wheels.
2. The unitary motor and power module of claim 1, wherein the housing is provided with means to engage with a static part of the pram, such as the frame, when the housing is placed between the pair of pram wheels.
3. The unitary motor and power module of claim 2, wherein the means comprises a protuberance extending from the housing, the protuberance configured to cooperate with a recess in the static part of the pram.
4. The unitary motor and power module of claim 2 or claim 3, wherein the means comprises a recess in the end of the housing, the recess configured to cooperate with a protuberance extending from the static part of the pram.
5. The unitary motor and power module of any preceding claim, wherein each drive shaft is splined.
6. The unitary motor and power module of any preceding claim, wherein each drive shaft is moveable from an extended position proud of the surface of the end of housing to a retracted position flush with, or lower than, the surface of the housing.
7. The unitary motor and power module of any preceding claim, wherein the terminus of each drive shaft is frustoconical.
8. The unitary motor and power module of any preceding claim, wherein the electric motor is operable to provide rotational force when one or both drive shafts are turned.
9. The unitary motor and power module of claim 8, further comprising at least one of a rotation sensor and a torque sensor.
10. The unitary motor and power module of any preceding claim, wherein a portion of the surface of the or each drive shaft comprises an electric contact electrically coupled to the battery.
11. The unitary motor and power module of any preceding claim, wherein a portion of the surface of the or each end of the housing comprises an electric contact electrically coupled to the battery.
12. The unitary motor and power module of any preceding claim, wherein the battery is a lithium ion battery.
13. The unitary motor and power module of any preceding claim, wherein the electric motor is a brushed or a brushless electric motor.
14. The unitary motor and power module of any preceding claim, wherein the motor is operable to act as a dynamo.
15. A powered pram comprising a unitary motor and power module according to any of claims 1 to 14.
16. The powered pram of claim 15, further comprising wiring passed through the frame of the pram to connect electrical devices to the battery when the housing is placed between the pair of pram wheels.
17. The powered pram of claim 16, wherein the electrical devices include one or more of lights, speakers, heaters, solar panels and sockets.
18. The powered pram of any of claims 15 to 17, wherein the pram includes control means for the electric motor.