Communications: electrical – Continuously variable indicating – With meter reading
Reexamination Certificate
1997-11-06
2001-03-20
Tokar, Michael (Department: 2819)
Communications: electrical
Continuously variable indicating
With meter reading
C340S870030, C340S432000
Reexamination Certificate
active
06204775
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a system for the wireless transmission of signals for a cycle.
2. Description of Background and Relevant Information
In general, the operation of the main mechanisms of a bicycle, such as the derailleurs and the brakes, is controlled by mechanical devices. Most often, handles or levers are provided on the handlebar or the frame which are connected by cables to the corresponding mechanisms: front brake, rear brake, (front) derailleur for positioning the chain on a gear wheel and (rear) derailleur for positioning the chain on a sprocket wheel.
These operations demand the attention of the cyclist and sometimes require effort.
In order to eliminate these drawbacks, French Patent Publication No. 2 654 698 proposes a wireless remote control system with a transmitter installed on the handlebar which transmits signals to the brakes and to the derailleurs. The proposed system also comprises a display of the operating parameters.
The range of the transmitter is short, no more than two meters. However, the proposed technology has not yet proven suitable for practical embodiments, since it does not provide a solution to the essential problems to be solved for this type of system.
In particular, as mentioned in the aforementioned French patent, the transmitters and receivers must be in positions such that there is no transmission interference constituted by obstacles such as the cyclist himself. When the transmitter is disposed in the front, for example on the handlebar, and the receiver is in the rear, particularly in the area of the derailleurs or the brakes, it is not possible to produce this condition.
SUMMARY OF THE INVENTION
An object of the present invention is to eliminate the aforementioned drawback.
According to one of its aspects, the invention is directed to a wireless control and/or measuring system for a cycle or cycles, wherein it includes a transmitter of control and/or interrogation signals whose transmitted carrier frequency is within a range such that the human body is substantially transparent for this frequency and such that the signal transmitted is not very directive, and wherein the signals transmitted by the transmitter are messages comprising a code specific to the system.
The choice of signals for which the human body is transparent enables a control or interrogation device to be disposed in front of the cyclist and a receiver to be disposed behind the cyclist.
The low directivity of the signal allows a simple embodiment of the antennae, and the code specific to the system prevents the transmitter of one cycle from operating a mechanism, such as the derailleur, of another cycle travelling nearby.
In order to solve the latter problem (the non-operation of a mechanism of a nearby cycle), it is also possible to limit the range of the transmitter. However, it has been observed that this limitation is not enough to solve this problem, since this range is at least equal to the distance between the handlebar and the rear derailleur and, with this range, the receiver of a nearby cycle would inevitably receive a transmitted signal.
If the receiver of a cycle picks up a transmission originating from a transmitter of another cycle, this receiver will not cause an undesirable operation (or an undesirable measurement), since it will know how to recognize that the message is not intended for it.
In a preferred embodiment, the transmitter carrier frequency is between 10 and 150 kHz.
In this frequency range, the electromagnetic waves are practically undisturbed by the human body and by the frame of the cycle. Moreover, broadcasting signals have different frequency ranges. Finally, these frequencies provide a comfortable bandwidth for the transmission of digital messages between the transmitter and the receivers.
Given that in a wireless communication system it is practically inevitable that a receiver will pick up signals that are not intended for it, if the reception of an interfering signal occurs at the same time as the reception of a wanted signal, the latter signal runs the risk of not being correctly received. In this case, the corresponding command will not be executed. The interfering signal can originate from the same cycle or from another cycle.
In order to prevent interference of this type, the invention provides a means for detecting signals transmitted by other systems, and the transmitter begins transmitting its control signal only when no interfering signal is detected. The detection of interfering signals is carried out either in the vicinity of the transmitter or in the vicinity of the receiver or receivers.
In one embodiment, a means is provided such that the transmission of a signal is only carrier out after a determined time T
E
following a transmission command if, at the time of this command, an interfering signal is detected, the duration T
E
corresponding to a duration of a control signal transmission. With this disposition, the control signals, which cannot be transmitted simultaneously, are transmitted in the order of the time sequence of the transmission requests.
The duration of the transmission of each message being on the order of several milliseconds, in case of simultaneous transmissions, the delay between the control command initiated by the cyclist and the effective execution of the command will be at least around 100 ms, which is perfectly compatible with proper operation.
It is possible for the interfering signal to reach the receiver but not the transmitter. In this case, if there is no secondary transmitter coupled to the receiver for communicating with the main transmitter, the transmitter will not have any information on the interference. In order to solve this problem, in one embodiment, it is provided for each control message to be transmitted repeatedly, the duration that separates the transmission of two successive identical messages being random, for example equal to a whole number of message transmission times T
E
. In this case, it is preferable for the repeated message to contain information on its rank, means being provided such that the repeated message is inoperative if the action commanded has already been performed as a result of the first message.
In one embodiment, each message or control signal is assigned an indication on the priority of its execution, for example, a braking command or a gear shift command takes priority over a reading of an operating parameter of the bicycle. In this case, the transmission of the priority signal enables the higher priority command to be transmitted before the other commands.
In a preferred embodiment of the invention, the modulation of the transmitted information, which is preferably digital, is a frequency modulation, which has the advantage of accepting a signal with a wide dynamic range, and thus of solving, in simple fashion, the problems of dispersions from one transmitter to another, power cell consumption, and different positions of the electronic components in a cycle. Moreover, this frequency modulation is not overly sensitive to interference.
According to another of its aspects, the invention relates to a wireless control and/or measuring system for a cycle which makes it possible to minimize electrical power consumption and thus maximizing the service life of the electric cells which supply power to the transmitters and receivers and minimizing their weight.
In order to solve this problem when the transmitter/receiver is not in use, either because the cycle itself is not in use or because the user is not using the control and/or interrogation functions, the invention provides for the de-activation of the receiver, with negligible power consumption, after the passage of a determined amount of time, for example on the order of several minutes, during which the receiver has not received a signal.
The de-activation consists of cutting off the power supply of the receiver and periodically re-establishing it, the duration of the supply of the power to the receiver being small relative to the duration of
Greenblum & Bernstein P.L.C.
Jeanglaude Jean
Mavic S.A.
Tokar Michael
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