Patent Application
20080023234
In the drawings,
The embodiment 100 may be an after market part that sold separately from the bicycle 101. In such case, the attachment arm 103 may have a mechanism that attached to the frame of any standard bicycle 101 using clamps or bolt-on hitch on the rear axle 102 or some other type. The mechanism can be quick-release so that the trailer 100 can be easily mounted or dismounted from the bicycle 101.
On the clamp 304, a pair of pressure/force meters 307 are installed on the front and back side of the lock pin 306 where the meters 307 are supported by the body of clamp 304. The top side of the pin 306 has no contact from the clamp 304 directly. Instead, its position is restricted by the pressure/force meters 307. When bicycle 101 is pulling the trailer 100, the momentum of trailer 100 will pull the clamp 304 to the back. Relative to the clamp 304, the pin 306 pushes to the pressure/force meter 307 on the front side of the pin 306. On the other hand, if brake is applied to the bicycle 101, the momentum of trailer 100 pushes the clamp 304 forward. In that case, the pin 306 pushes to the pressure/force meter 307 on the back side of the pin 306. The pressure/force meter result is passed to the controller 605 through a connecting cable 308.
Other embodiments may have different configuration for the attachment mechanism and may have different method to measure the pulling/pushing forces from the bicycle 101 to the trailer 100. Those skilled in the art may be able to implement the present invention in many different ways without violating the spirit or intent of the present invention.
In this design, the arm 402 can be easily removed from the frame 401 that reduce the overall size for transportation or storage. To install the arm 402, users simply slide in the arm 402 into the restrainer 403, insert the lock pin 404 and secure with an hairpin cotter. The design also reduce the wiring need from the pressure/force meter 405 to the controller 605 that is mounted on the back of the trailer 100. Other embodiments may have different configuration for the restraining mechanism and may have different method to measure the pulling/pushing forces from the bicycle 101 to the trailer 100. Those skilled in the art may be able to implement the present invention in many different ways without violating the spirit or intent of the present invention.
As illustrated, the motor 502 is aligned orthogonal to the wheel axle. The design reduces the space needed for the motor 502 on the side of the carrying compartment area of the trailer 100. Because the wheel 504 is required to move without electric power applied to the motor 502, the gear box 503 has to be able to be driven from motor 502 or wheel 501. When regenerative break is applied, the motor 502 functions as a generator driven by the wheel 504. The generated electricity is fed to recharge batteries 607 through the controller 605.
Use of enclosed gear box 503 as illustrated reduces the exposed moving parts, which increases the safety for the children carrying device. Nevertheless, alternative embodiments may use chain or belt or other types in place of the gear box 503 that connects motor 502 and wheel 504. The motor may be mounted parallel to the axle of the wheel 504 or in different location. Those skilled in the art may be able to implement the present invention in many different ways without violating the spirit or intent of the present invention.
The gear box 503 may include an electrically controlled clutch that disengage the wheel 504 from the motor 502 completely if no power is applied to the motor 502 or no regenerative brake is applied.
In some embodiments, the wheels 504 may be mounted on suspensions such as coil springs or leaf springs to make the riding more comfortable for the carried children. In such configuration, the motor 502 and the gear box 503 may move tightly with the wheel 504 to eliminate the need for additional Constant Velocity (CV) joint or U-joint axles. Such type of design allows the use of harder tire that decreases friction thus increases the battery life without sacrificing riding comfort.
The embodiment has both wheels 504 driven by separate motors 502. Having two separate motors 502 for each wheel 504 eliminate the disadvantages of just one motor. With one motor, the system can only drive one wheel in a simple configuration and leave the other one free running which causing force imbalance and unnatural twist to the bicycle's 101 frame. Or a common transaxle with differential gear is required to deliver the power to both wheels without locking the wheels during a turn. The cost of the said differential gear system is too high and a transaxle crossing the trailer 100 also make the system design inflexible for highly fashioned consumer product.
With two separate motor 502, the power is delivered to both wheels 504 evenly without the cost of differential gear and the transaxle. Each motor 502 can be located independently, that maximize the design possibility. The motor 502 can run at different speed so that the wheels 504 are not locked during a turn. For some sporty trailer design, the wheel 504 can even installed with an angle expand outward to the ground. The motor 502 can also be smaller in size compare to one-motor design. The smaller motor size is important for trailer 100 carrying children that a safe and comfortable accommodation space is a must. Some room or corner has to be given out to one big motor.
The battery packs 607 can be rechargeable or non-rechargeable. The two different types of battery may be used at the same time. Regenerative brake is only available when at least one battery pack 607 is rechargeable. Mixed use of the battery types has benefit to the users. Since all batteries have limited capacity, use only rechargeable battery constrains the operation time of the trailer 100 also requires sufficient charge before each time of use. The present invention can be powered by rechargeable and the non-rechargeable at the same time so that the operator may obtain extra alkaline battery during the trip for extra period of continuous operation. The controller 605 automatically detects the battery type and decides the best use of each battery pack 607.
The charger for the battery pack 607 is not mounted on the trailer 100. In some of prior art, the battery charger is an integrated part of the trailer 100. In that case, the trailer has to be located close enough to the power source for recharging. For the present embodiments, instead of plug-in the trailer 100 to wall electric outlet, user removes the battery pack 607 from the trailer 100 to a separate charger that in turn connects to the wall electric outlet in an easier accessed location while the trailer 100 may be kept in storage. This configuration also allows the user to obtain extra battery packs 607 for extended use. Nevertheless, the depicted configuration does not limit the spirit or intent of the present invention.
A dial 606 is located on top of the controller 605 that is accessible from inside of the trailer 100. The dial 606 controls the power assistance level applied to the motor 502. If low assistance is set, bicycle 101 will spend more effort on pulling the trailer 100 while the battery life can last longer. If high assistance level is set, the user of the bicycle 101 feels almost no load from the trailer 100 although the battery will be depleted faster.
The embodiment may have a main switch 704 that shut off the power completely. The power assistance level is set from a device that may be a potentiometer 706. A pair of pressure/force meter 707 is connected to the controller for the push/poll force measurement. A rotation meter 708 is also connected to the controller that measures the wheel rolling direction and speed. The reading of these two meters forms the major decision making input to the controller. If the wheel is rotating backward or moving with speed lower than an active threshold, no power or braking will be applied. The active threshold is set at a level that prevents the trailer 100 from making jittery move at very low speed. User of the bicycle 101 will have to use his (her) force to tow the trailer 100 at speed below the active threshold. Above the active threshold, the controller 701 applies more power to speed up the motor 709 if the pressure/force meter 707 senses high on pulling force. On the other hand, if the pressure/force meter 707 senses very low on pulling force, or even pushing force, the controller may reduce the power to slow down the motor 709 or apply regenerative brake.
Some embodiments may have an additional switch installed on the handle bar of bicycle 101 that force the regenerative brake on the trailer 100. When user wants to slow down the bicycle, instead of applying brakes on the bicycle 101, he (she) may force the regenerative brake on the trailer 100. More electric power can be reclaimed into the battery pack 702, hence extend the operation distance for the battery pack 702. The said switch may be integrated into the bicycle's 101 brake lever.
The motor 709 in the present embodiment may be a 12V DC motor. Other types of motor, like AC synchronous motor, may be used as well. The size of the motor 709 may vary depending on the designated load and use of the trailer 100. Typically, for carrying one child on a paved road, 200 W combined power is enough for the application. Gear type and ratio also varies depending on the application.
The control mechanism to the motors 709 may be pulse width modulation control, variable reluctance control, phase control or other motion control that can vary the speed of a motor. The optimum configuration depends on the motor type. If synchronous motor is used, separate rotation meter 708 may be omitted since the motor 709 has that function included already.
Unlike previous inventions that are designed for assisting the rider by pushing the bicycles, the present invention is meant to self propel the trailer only at the level to keep up with the leading bicycle. User of the bicycle still has to spend full effort riding the bicycle. The benefit from the present invention is for the user to operate a standard bicycle with a trailer for a leisure trip without spending extra effort to move the trailer. In this type of leisure riding, user does not want any power pushing the bicycle, which defeats the purpose. However, the extra load from the trailer makes it harder for the rider to enjoy the trip. With the present invention, the user may have the most joy from the trip.
The present embodiment is easy to operate. There is no need for any sort of adjustment during riding time, once the assistance level is set. The controller does all the motor power adjustment based on the readings from the pressure/force meter and rotation meter. The basic mechanical structure of the trailer has no difference from the conventional, non-powered version. There is no need to modify the standard bicycle other than installing a hitch device to mount the trailer. The rotation meter reading that can be translated into speedometer and the fuel gauge can be optionally located on the handle bar of the bicycle, which provides extra information to the rider.
The present embodiment also increases the safety of the trailer that carrying children. With the on-board meters, the controller is able to detect certain type of dangers thus applies brake or removes power from the motors accordingly to avoid accident like roll-over from happening.
The present invention provides helpful features for those parents who like to bring their children or people who like to bring their heavy outdoor gear on a recreational ride but hesitate to do so due to the extra effort on pulling the trailer, especially on a hilly area. The ease of operation makes the transition from conventional type easy. The basic structure of the embodiment and the attachment mechanism are very close to the conventional non-powered trailer, which makes the manufacturing also very easy for existing trailer manufacturers.
The foregoing description of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and other modifications and variations may be possible in light of the above teachings. The embodiment was chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and various modifications as are suited to the particular use contemplated. It is intended that the appended claims be construed to include other alternative embodiments of the invention except insofar as limited by the prior art.
