Abstract:
A process and system for measuring information concerning movement factors, and to values, which can be calculated therefrom, particularly stride length, stride number, stride time and running time, via a pair of shoes (1, 2), each of which is provided with a transmitter (S1 or S2), a receiver (E1 or E2), and a signal time measuring device (counter Z1 or Z2). A direct signal (t dir .) emitted by the front shoe (1) in response to ground contact is received by the rearward shoe (2), is transferred in conformance to time parameters to the first shoe 1 as a reflected signal (refl.). The direct and reflected signals as well as the readouts of both counters (Z1 and Z2) are transmitted to a computer unit, particularly, a high-frequency computer unit for use in determination of the movement information.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a process and shoe system for measuring information concerning moving sequences in running disciplines, and to value which can be calculated based thereon, particularly information concerning stride length, stride rate, stride time, and running time determined with the aid of a pair of running shoes having a transmitter and receiver in each shoe as well as a sensor which triggers emission of a signal when one of the shoes makes contact with the ground. 
     A process and system of this kind is disclosed in German Offenlegungsschrift No. 34 05 081 (which corresponds to the present assignee&#39;s allowed U.S. Pat. No. 4,703,445), wherein the forward shoe emits a first signal to the rearward shoe, each time there is ground impact with the shoe, while simultaneously transmitting an activation signal to a remote computer unit. The rearward shoe subsequently sends a second signal to the forward shoe, and from there, to the computer unit. Based on the time delay between receipt of these two signals, information concerning the leg or running speed, and/or stride length of the runner can be detected and emitted. In commonly assigned U.S. Pat. No. 4,736,312, a further development of this system is disclosed wherein the jump or flight time of the wearer&#39;s stride (occurring during a leap phase wherein both feet are off the ground) can be considered as well. To this end, a second sensor is provided in the other shoe to detect when the trailing foot is lifted off from the ground and, based upon the time and origin of signals from both shoes, movement characteristics of the user are determined. 
     SUMMARY OF THE INVENTION 
     It is the primary objective of the present invention to improve the accuracy of such a measuring process and system, and further, to provide that the process and system simultaneously provide information concerning leap time and concerning values which can be derived therefrom in a simple and accurate manner. 
     This objective is achieved in accordance with the features of the preferred embodiments described herein. In accordance with particular features, a first counter is provided in a first shoe that is activated upon ground impact of the first shoe and deactivated upon receipt of a reflected signal from the second shoe, while a second counter is provided in the second shoe which is activated during lift-off of the second shoe and deactivated based upon receipt of the ground contact signal of the first shoe. 
     The use of two counters in combination with the transmitting-receiving devices permits measurement of the leap time and the signal travel time easily and accurately, and with a minimum of components. 
     Another means for simplifying the process and system is the use of a basic transmitter-receiver converter, which can be effectively switched from the transmitting to the receiving mode. 
     These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, several embodiments in accordance with the present invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 schematically depicts the start of the runner&#39;s leap phase at the time of rearward foot lift-off and initiation of the process of the invention; 
     FIG. 2 schematically depicts the end of the leap phase when the forward foot is put down on the ground; 
     FIG. 3 illustrates a basic switch diagram of the transmitter and receiver devices of the shoe system of the invention; and 
     FIG. 4 is a flow chart depicting performance of the inventive process with the system of the preferred embodiment. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 shows the position of a first shoe 1 (which happens to be forwardly directed) relative to a second shoe 2 (which happens to be rearwardly directed) at a point in time to which, for describing the invention, will be considered the commencement of the process and is occurring at initiation of the leap phase. 
     FIG. 2 shows the relative positions assumed by shoes 1, 2 at a subsequent time t 1 , at which the jump phase initiated in FIG. 1 is completed. 
     In FIG. 4 the signals transmitted and received at the first shoe 1 are depicted above time axis t, and those emitted by the second shoe 2 are shown below axis t, during various time segments. 
     Each shoe 1 and 2, respectively, is provided with a transmitter unit and a receiver unit S1, E1, S2, E2 (FIG. 3), particularly units which function on an ultrasonic basis. Advantageously, only one converter 3 or 4, respectively, is provided in this case, the converter being capable of operating in both transmitting and receiving modes. The changeover from one mode to the other occurs in the respective transmitter-receiver units S1, E1 or S2, E2. It is also preferable if both transmitter-receiver units S1, E1 or S2, E2 are constructed in the same manner. 
     A pressure sensor D1, D2 is provided in each shoe. Upon ground impact of first shoe 1, pressure sensor D1 of the first shoe 1 causes emission of an output signal dir. (direct ray) from transmitter S1 and which is delivered to receiver E2 from converter 4. After emission of the output signal dir., the receiver E1 is coupled to converter 3 and upon receipt of the output signal dir., in shoe 2, converter 4 is switched from its receiving to its transmitting mode, whereafter a reflected output signal refl. is emitted from shoe 2 to first shoe 1, where it is subsequently received by converter 3 and receiver E1. 
     Moreover, each shoe 1, 2 contains a time-measuring device (counter Z1, Z2 and first shoe 1, additionally, is provided with storage means SP for storing at least one value transferred from the counter. Additionally, another transmitter S3 is provided in first shoe 1, which is capable of transmitting data obtained from the counters Z1, Z2 of the first shoe 1 and the second shoe 2, which may have been stored temporarily in storage means SP, to a remote computer. 
     The operating mode of such arrangement is described by way of the flow sheet, depicted in FIG. 4 as follows: 
     Second counter Z2 is activated via pressure sensor D2 at time point t o  of the running period (FIG. 1) at which a leap phase, when neither shoe 1, 2 touches ground B, commences by second shoe 2 lifting off ground B. 
     After leap time t s , shoe 1 hits ground B at time point t 1  (FIG. 2), which causes pressure sensor D1 to address transmitter S1 and to emit direct ray dir. as an output signal to rearward shoe 2 via converter 3. After transmittal of output signal dir., converter 3 is connected to receiver E1 during switch-over period t um , effecting a change to the receiving mode, with first counter Z1 being started at time point t 2 . 
     After time t dir . of output signal dir. has elapsed, this signal is received by converter 4 at time point t 3  and is processed in receiver E2, whereby the signal to be processed is available after a detection period, for example, after the transient process of the receiving circuit, at time point t 3 . This signal is utilized for stopping the second counter Z2. Accordingly, the value at counter Z2 represents leap time t s  plus travel time of direct ray t dir . from first shoe 1 to second shoe 2, plus detection time t det . (between points t 3 , t&#39; 3 ). 
     After a delay time t v  in second transmitter-receiver S2, E2, a reflected output signal refl. is emitted from shoe 2 to shoe 1 at time point t 4  by transmitter S2 via converter 4. Signal refl. is received at shoe 1 after a travel time t refl . at time point t 6 . The corresponding signal is available at time point t&#39; 6 , again, only after a detection time t det . has elapsed. This signal is utilized to stop first counter Z1. 
     By selecting the delay time t v  to equal the switch-over time t um , the value at counter Z1 corresponds exactly to the sum comprised of the travel time of output signals dir. and refl., i.e., t dir . +t refl .. 
     In accordance with the features of the invention, the value at second counter Z2 is emitted to shoe 1 after release of the reflected output signal refl., after time point t 4 . This occurs here by the emission of a sequential burst FB (or time multiplex signal) at time point t 5  subsequent to a corresponding time lag from t 4  to t 5 , representing leap time t s  plus the travel time of direct output signal t dir . plus, if appropriate, an interval time t p . 
     In this case, interval time t p  is equal to the time interval from time point t&#39; 6  at which the first counter Z1 was stopped to time point t 7 , at which time first counter Z1 is restarted. 
     After travel time t FB  has elapsed, sequential burst FB is received by receiver E1 at time point t 8 , whereby the processing signal is available at time point t&#39; 8  after detection time t det .. At this point, the first counter Z1 is stopped by sequential burst FB. 
     During time interval t p , the first value determined by counter Z1 is stored in a storage unit of storage means SP. 
     Starting with time point t&#39; 6 , additional transmitter S 3  of shoe 1 is activated and the value which is stored in storage SP, and, subsequently, also the second computed value corresponding to time t FB , are emitted to a remote receiver R, from which they are fed to a remote computer unit C. Advantageously, the transmitter S3 is a transmitter of high-frequency electromagnetic wavelength, while the radiating means 5 consists of an appropriate antenna. 
     Accordingly, information concerning the double travel time of direct output signal dir. and the leap time t s , which is increased by the amount of the single travel time t dir ., are already available in the computer, and prior to that time, are available in first shoe 1. Information as to the actual leap time t s  can be obtained from this data, whereby it is advantageous if such information is obtained in the microprocessor of the remote computer unit after the emission of the values to the remote computer unit since the arithmetic necessary therefor can be carried out by it without any difficulty. 
     In order to ensure transmittal of the values recorded at the second counter Z2 in the short time available, such transmittal occurs during a time frame which is reduced by a factor K. At the same time, first counter Z1 is addressed at a frequency f 2  during its second counting period which is increased by factor K relative to the frequency f 1  utilized in its first counting period. Accordingly, the transmittal time between time points t 4  and t 5  is: 1/K·(t s  +t dir .)+t p . 
     If the user of the inventive process and system changes his motion from running to walking, the leap phase, and inherently, the leap time t s , are eliminated. Time point t o  in every case then is after time point t 1 . Second counter Z2 having been started is not stopped by direct output signal dir. in this instance and, accordingly, is permitted to run down (assuming use of a countdown type timer). In correspondence therewith, there is no recording of leap time, no transmittal of sequential burst FB, and, thus, no signal to stop counter Z1 which has been activated a second time. This causes counter Z1 also to run down, and the only value transmitted to the computer unit is the value t dir . +t refl ., which was obtained during the first activation of counter Z1. Unless both shoes are provided with lift-off and contact detecting and signaling arrangements (which is not the case in the illustrated system), the above processing will occur only every other stride, i.e., will not occur in the stride from when shoes 1 and 2 are reversed relative to their positions shown in FIGS. 1, 2. However, by computation, with the frequency rate as a given factor, the sum of travel times t dir . +t refl . provides information concerning the double distance of shoes 1 and 2, and, consequently, the double stride length. 
     In order to increase the transmittal accuracy, it is advantageous to transmit the signals emitted from the first shoe 1 to the remote computer unit in a suitable code, permitting recognition and correction of transmittal errors. In similar manner, the leap time t s  recorded at shoe 2 can be transmitted to shoe 1 in encoded form. 
     It is noted that, with respect to aspects of this invention that are in common with corresponding aspects of the initially mentioned commonly assigned U.S. patent applications, reference may be made thereto for further details. For example, Ser. No. 701,194 shows manners for mounting sensors, transmitters, etc. in a shoe sole. 
     While we have shown and described various embodiments in accordance with the present invention, it is understood that the same is not limited thereto, but is susceptible of numerous changes and modifications as known to those skilled in the art, and we, therefore, do not wish to be limited to the details shown and described therein, but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.