Abstract:
An acoustic pulse transfer device according to the invention has one or more carrier segments that can be connected together to transport acoustic pulses through them. Acoustic pulses generated by events in a first segment are transported through a second segment, which may or may not have its own acoustic pulse generator generating acoustic pulses in response to different events. Acoustic pulses generated in the first and second segments are then independently transported through a third segment. Any number of such segments can be connected together. Typically, acoustic pulses are generated by compressing a pneumatic tube in a carrier segment. The pneumatic tube is connected to a substantially non-compressible acoustic pulse carrier tube connected to the segment&#39;s pneumatic tube through a trough in a wall separating the pneumatic tube from the acoustic pulse carrier tube. Multiple carrier segments can be linked together so that a acoustic pulse generated in a distant carrier segment can be transported through one or more segments toward a device actuated by the acoustic pulse such as a counter. The invention is particularly useful in traffic counting applications.

Description:
FIELD OF THE INVENTION 
   The invention relates to acoustic pulse activated systems and finds particular use in event counting systems, such as traffic counters. In particular, the invention relates to a method and apparatus for transferring an acoustic pulse. 
   RELATED ART 
   Systems exist which record events by counting pneumatic pulses. Vehicular traffic counters, which produce pulses when a vehicle crosses over a pneumatic tube, are one example of such systems.  FIG. 1  illustrates one such conventional vehicular traffic counting system.  FIG. 1  shows a system configured to count two lanes of traffic using four pneumatic tubes connected to a conventional acoustic pulse counter, used in traffic counting applications. In  FIG. 1 , a vehicle travelling in Lane  1  crosses and compresses pneumatic tubes  101 ,  102 ,  103  and  104 , thereby creating four acoustic pulses. A vehicle travelling in lane  2  crosses only pneumatic tubes  102  and  104 , creating only two acoustic pulses. Based on the timing of the acoustic pulses it receives, counter  105  determines whether the vehicle has passed in lane one or lane two and increments the count appropriately. One difficulty with such systems is that they require a large number of pneumatic tubes, which must be individually connected to the counter. The large number of tubes and their individual connections requires long set-up times. Such systems are also susceptible to reliability problems resulting from the number of vulnerable connections. In addition, the pneumatic tubes themselves are subject to damage from the constant stress induced by vehicular traffic. 
   SUMMARY AND OBJECTS OF THE INVENTION 
   In view of the limitations of conventional systems, it is an object of the invention to provide an acoustic pulse counter system that is simpler and easier to use than conventional systems. 
   A system according to the invention employs a protected acoustic tube that can be connected to a pneumatic tube to allow transfer of an acoustic pulse. According to the invention, one or more acoustic tubes are inserted into a protective carrier. The protective carrier also contains a pneumatic tube that can be connected to any one of the acoustic tubes to count the desired acoustic pulses. The protective carrier can be configured in carrier segments which can be used alone or can be connected together to count events occurring in more than one channel. One example application is the use of several segments to count individual lanes of vehicular traffic. 
   A system according to the invention is easier to set up and more reliable than conventional systems. According to the invention, a carrier segment has a base member with one or more acoustic pulse carrier tubes therein. The acoustic pulse carrier tubes are formed of a substantially non-compressible material, such as metal or hard plastic, to allow free transmission of acoustic pulses without undesired noise pulses. A carrier segment may also have an acoustic pulse generator, such as a compressible pneumatic tube. The acoustic pulse generator, such as the pneumatic tube, is connected to one or more selected acoustic pulse carrier tubes which transmits the generated acoustic pulse to the end of the carrier segment for connection to a counting device directly or through other carrier segments. Such other carrier segments may serve solely as a conduit or may also have the ability to generate other acoustic pulses to be carried through other acoustic pulse carrier tubes therein to form a multi-channel counting device. The carrier segments may be configured to contain as many acoustic pulse generators, such as compressible pneumatic tubes, and acoustic pulse carrier tubes as desired. The carrier segments can be assembled at a factory or can be assembled on site by inserting the desired acoustic pulse carrier tubes and pneumatic tubes. Since on site customization is possible, a system according to the invention is particularly suited to being supplied in kit form. Moreover, carrier segments according to the invention may be used alone or in combination with conventional pneumatic counting tubes and can be used with conventional acoustic pulse counting devices. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is described herein with reference to the drawings in which: 
       FIG. 1  illustrates a conventional traffic counting system configuration; 
       FIG. 2  illustrates an event counting system according to the invention 
       FIG. 3  illustrates a carrier segment according to the invention having space for at least two acoustic pulse carrier tubes; 
       FIG. 4  illustrates a carrier segment according to the invention having slots for additional acoustic pulse carrier tubes; 
       FIG. 5  is a perspective view illustrating an empty carrier according to the invention 
       FIG. 6  is a perspective view illustrating a carrier according to the invention having an acoustic pulse carrier tube in one of its slots connected to an acoustic pulse generating tube therein; 
       FIG. 7  is a perspective view of a carrier according to the invention having an acoustic pulse carrier tube in each of its slots and an acoustic pulse generating pneumatic tube therein; 
       FIG. 8  illustrates another configuration of a carrier segment according to the invention with acoustic pulse carrier tubes embedded therein; 
       FIG. 9  illustrates another configuration of a carrier segment according to the invention in which acoustic pulse carrier tubes can be inserted from a bottom portion of the carrier segment; 
       FIG. 10  illustrates one configuration of a carrier segment connector; 
       FIG. 11  illustrates another configuration of a carrier segment connector; 
       FIG. 12  illustrates an end molding for sealing a carrier segment according to the invention. 
       FIG. 13  illustrates another optional embodiment with a window to provide hand access and strain relief. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   For purposes of illustration only, the invention will be described in the context of a vehicular traffic counting system. Those of ordinary skill will recognize that the invention is not limited to vehicular traffic counter applications and that the invention can be used in any context where it is desirable to transmit an acoustic pulse for any purpose. 
   An exemplary event detector according to the invention is shown in  FIG. 2 . Those of ordinary skill will recognize that the detector shown in  FIG. 2  is by way of example and not limitation, as traffic detectors can take numerous physical shapes and be configured to accommodate any number of traffic lanes.  FIG. 2  illustrates a traffic detector system in a three lane counter configuration. In this configuration carrier segments  201 ,  202  and  203  are appropriately connected together for connection to a conventional multi-channel traffic counter  204  activated by acoustic pulses. Such pulses are created when traffic passes over a carrier segment. The carrier segments are connected together using connector elements  205 ,  206  and  207  discussed further herein. As previously noted, conventional systems employ a plurality of pneumatic tubes of different lengths individually connected to one or more counters in order to count multiple lanes of traffic. The present invention provides the advantage of allowing a user to configure a system to count any number of traffic lanes quickly and easily simply by connecting together several carrier segments prepared in advance to count individual lanes as desired. Moreover, the segments can be prepared on site and modified to accommodate changing needs and circumstances as discussed further herein. Indeed, a product according to the invention can also be provided in kit form, as discussed further herein. Those of ordinary skill will recognize that a carrier can be formed by one or more carrier segments. 
     FIG. 3  is a side view of a carrier segment according to the invention. For purposes of illustration only, the carrier segment shown in  FIG. 3  is configured to accommodate two acoustic tubes and one pneumatic tube. The carrier can be made to accommodate any desired number of acoustic and pneumatic tubes. The only limits on the number of acoustic and pneumatic tubes that can be accommodated in a carrier are those size and flexibility constraints imposed by the user and designer.  FIG. 4 , for example illustrates a carrier that can accommodate a larger number of acoustic tubes. 
   Returning to  FIG. 3 , carrier segment  301  has a base portion  300 . Within base  300  is a pneumatic tube slot  302  and acoustic tube slots  303  and  304 . The pneumatic tube slot  302  is separated from acoustic tube slots  303  and  304  by walls formed of carrier material portions  305  and  306 .  FIG. 3  illustrates alternative acoustic tube slot shapes. Slot  303  is shown having a U-shape configuration with a substantially uniform width and straight interior edge for most of its depth, for ease of placing the acoustic tube in the slot. Slot  304  is shown having a narrow opening at the insertion end with a wider radius where the acoustic tube remains after being placed in the slot. A portion  307  of carrier material resiliently springs over a portion of the acoustic tube thereby providing it additional protection from wear and tear. Either configuration of tube slot may be used. In addition, other tube slots configurations are also possible within the scope of the invention.  FIG. 4  illustrates by way of example and not limitation one embodiment with multiple slots for pneumatic and acoustic pulse carrier tubes. Other configurations within the scope of the invention may also be formed using different numbers and arrangements of slots for acoustic pulse carrier tubes and pneumatic tubes. 
     FIGS. 5 ,  6  and  7  illustrate perspective views of carrier segment  301  at various stages of assembly.  FIG. 5  illustrates an empty carrier segment  301  in perspective having tube slots  303  and  304 , both with the tube slot configuration described above with respect to slot  304 .  FIG. 6  shows carrier  301  with an acoustic pulse carrier tube  308  inserted into acoustic tube slot  304 .  FIG. 7  illustrates carrier  301  with acoustic pulse carrier tube  309  inserted into acoustic tube slot  303  and pneumatic tube  310  inserted into pneumatic tube slot  302 . Pneumatic tube  310  can be any type of pneumatic tube known to those of ordinary skill. Low Profile Hose (LPH) is one form of pneumatic tube that would be acceptable in this application. The acoustic pulse carrier tubes  308 ,  309  can be any tubes of sufficient durability that will not crush and will allow an acoustic pulse to move through them. For example the tubes can be made of metal or plastic. 
   As shown in  FIGS. 2–9 , carrier  301  is generally shaped like a ramp. While this may be an appropriate shape for vehicular traffic counting applications, other shapes can be used in other applications without departing from the scope of the invention. 
     FIGS. 8 and 9  illustrate other forms of a carrier according to the invention.  FIG. 8  illustrates a form where the acoustic pulse carrier tubes  308  and  309  are built into the carrier rather than being inserted.  FIG. 9  illustrates a form where the acoustic pulse carrier tubes  308  and  309  are inserted into acoustic tube slots from a bottom portion of carrier  301 . Of course, in any configuration, pneumatic tube  310  can also be built into the carrier  301  rather than being inserted. 
   In any configuration, it is necessary to form an acoustic pulse generator to generate an acoustic pulse and transmit the desired acoustic pulse from a pneumatic tube to an acoustic pulse carrier tube. This is accomplished by connecting selected acoustic pulse carrier tubes to the pneumatic tubes as desired to transmit an acoustic pulse corresponding to a particular event. Connection of the acoustic pulse carrier tubes to the pneumatic tubes is accomplished by forming a passage, such as trough  320  in  FIGS. 5 and 6 , in the material between the pneumatic tube and the acoustic tube slots. The trough is used as passage to connect the pneumatic tube to the corresponding acoustic pulse carrier tube in the trough. An example is shown at connection  322  in  FIG. 6 . Here pneumatic tube  310  connects to acoustic pulse carrier tube  308  through a trough between pneumatic tube carrier slot  302  and acoustic pulse tube carrier slot  303 . Such troughs can be formed at the time of manufacture, or can be formed, for example, by cutting away a portion of the material  305  or  306 . Such cutting can be done on site and those of ordinary skill will recognize that a carrier segment can be reconfigured simply by cutting new troughs and making new connections between the pneumatic tube and the acoustic pulse carrier tube. One makes the connection simply by routing the pneumatic tube through the passage or trough and connecting the pneumatic tube to the free end of the acoustic pulse carrier tube within the trough. Depending on the configuration change required, it may be possible to use the same pneumatic and/or acoustic pulse carrier tube. In any case, replacing either the pneumatic tube or the acoustic pulse carrier tube or both allows indefinite reuse of the carrier segment. 
   Depressing the pneumatic tube, for example by passing an item to be counted over it, generates an acoustic pulse. Since the pneumatic tube is connected to one of the acoustic pulse carrier tubes in a trough as discussed above, the acoustic pulse is transmitted from the pneumatic tube to the acoustic pulse carrier tube connected to that pneumatic tube. Acoustic pulses are thus transmitted from the pneumatic tube to one of the acoustic pulse carrier tubes, which carries the acoustic pulse through the carrier segment toward the counting device. Carrier segments can be connected together in order to carry an acoustic pulse from a distant segment through one or more carrier segments nearer the counting device. These carrier segments can also be responsive to separate stimuli by connecting a pneumatic tube in that segment to a different acoustic carrier tube. 
   It will be recognized that for events occurring in separate lanes, multi-channel counts can be recorded depending on the routing of connections between the pneumatic and acoustic tubes. For example, by using one acoustic tube for each of several vehicular traffic lanes or processing lines in a manufacturing plant, and connecting the pneumatic tube to an acoustic tube, the acoustic tube can route the pulse to a counter that counts the number of events in that lane 
   Returning to  FIG. 2 , this Figure schematically illustrates a traffic counter system configured according to the invention. For ease of illustration,  FIG. 2  does not detail the pneumatic tubes connected to the acoustic pulse carrier tubes. In FIG.  2 , lane  3  is configured such that a pneumatic tube  251  in the portion  201  is connected to an acoustic pulse carrier tube  210  using the connection methods discussed previously herein. Thus, a vehicle passing over the pneumatic tube  251  in carrier segment  201  generates an acoustic pulse that is transmitted to acoustic pulse carrier tube  210 . As the last carrier segment, segment  201  has an end molding  211  built in or inserted into the acoustic pulse carrier tube in order to seal the acoustic pulse carrier tube that carries the pulse and prevent the acoustic pulse from escaping from that acoustic pulse carrier tube. While  FIG. 2  shows the end molding  211  inserted into all the acoustic pulse carrier tubes, those of ordinary skill will recognize that the end molding need only be inserted to seal the acoustic pulse carrier tube that is connected to the pneumatic tube to carry an acoustic pulse. Remaining acoustic tubes in the carrier segment that are not used need not be sealed with an end molding. 
   The acoustic pulse that was transferred to acoustic pulse tube  210  in carrier segment  201  proceeds through connector  205  to acoustic tube  212  in carrier segment  202 . The acoustic pulse next proceeds through connector  206  to acoustic pulse carrier tube  213  in carrier segment  203 . Finally, the acoustic pulse proceeds through connector  207  to counter tube  214  which routes the acoustic pulse to the counting device  204 . 
     FIG. 2  further illustrates that segment  202  has acoustic tube  215  which receives pulses from a pneumatic tube  252  compressed by vehicles travelling in a second traffic lane. Acoustic pulses travel through acoustic pulse carrier tube  215  and connector  216  through acoustic pulse tube  217  in carrier segment  203 . The pulses are then routed through connector  218  to counter tube  219  which routes the acoustic pulse to counter  204 . In this configuration carrier segment  202  serves two purposes. First, carrier segment  202  serves to carry acoustic pulses generated in lane  3  toward the counter. Independently, carrier segment  202  generates acoustic pulses for traffic in lane  2  and routes those pulses toward the counter. 
   Carrier segment  203  operates in a similar fashion to count traffic travelling in lane  1  and to facilitate passage of acoustic pulses generated by traffic in lanes  2  and  3 . In the case of lane  1  the user connects a pneumatic tube  253  to acoustic pulse carrier tube  220  for connection to the counter through connector  221  and counter tube  222 . Alternatively, since it is not necessary to transmit the acoustic pulse through any additional carrier segments, the user could simply connect the pneumatic tube  253  directly to counter tube  222  or directly to the counter  204 . 
   Those of ordinary skill will recognize that any custom configuration is possible. For example, if a user wished to count events in lanes  2  and  3 , but ignore events in lane  1 , the user could configure carrier segment  203  without an acoustic pulse generator, for example by omitting the pneumatic tube. In this case carrier segment  203  serves merely as a conduit to carry acoustic pulses from lanes  2  and  3  in acoustic pulse tubes  213  and  215 . 
   As illustrated in  FIG. 2 , the acoustic pulse carrier tubes in segments  201 ,  202  and  203  are slightly shorter than the length of the segments themselves. As previously noted, the acoustic pulse carrier tubes should be substantially non-compressible in order to provide a clear transmission path for the acoustic pulse and to prevent the introduction of unwanted noise pulses. Making the acoustic pulse carrier tubes of a length such that they do not extend all the way to the edge of the carrier segment is preferred in order to minimize such effects. This approach allows the acoustic pulse carrier tubes to remain totally within the carrier material, providing additional cushioning and isolation from such undesired effects. As shown in  FIG. 2 , connectors  205 ,  206  and  207  extend into the carrier segments to connect to the acoustic pulse carrier tubes  210 ,  212  and  213  within the carrier segment in order to facilitate this protection of the acoustic pulse carrier tubes. A similar approach is applied to the remaining connectors and acoustic pulse carrier tubes. 
   Connectors joining the carrier segments can have any suitable shape and configuration to accommodate the transmission of the acoustic pulses. For example,  FIG. 10  illustrates one form of segment connector  1001  to join and cross over between the pneumatic tube and the acoustic pulse carrier tubes in connecting segments. The segment connector in  FIG. 10  would find use in connecting segments having multiple acoustic pulse carrier tube slots. The cross hatched areas  1002 ,  1003  and  1004  represent arms of the segment connector that are plugged either when manufactured or by inserting plugs on site. The plugs in these segments prevent a pneumatic or acoustic pulse from travelling down that arm. As a result, an acoustic pulse is routed through the clear paths from one acoustic pulse carrier tube in a first carrier segment connected to arm  1005  and through arm  1006  to a first acoustic pulse carrier tube in a second carrier segment connected to arm  1006 . Similarly, an acoustic pulse in a second acoustic pulse carrier tube in the first carrier segment is connected to arm  1007  and routed through arm  1008  to a second acoustic pulse carrier tube in the second carrier segment. Any number of such clear paths can be incorporated into the segment connectors, for use depending on the application. Those of ordinary skill will recognize that such segment connectors can be made in any desired configuration or shape and can be manufactured in such shapes and configurations or assembled on site with interlocking parts into desired shapes and configurations. Similarly, the sealed arms of such connectors can be formed by manufacturing the arms with permanently closed passages or by inserting individual plugs into the arms being sealed. 
     FIG. 11  illustrates a plurality of straight-through connectors  1101  that can be used to allow acoustic pulses to travel from one carrier segment to another. Such straight-through connectors are shown in  FIG. 11  connected together on web  1102  to form a single unit. However, individual straight-thorough connectors can also be used. 
     FIG. 12  illustrates an end block  1201  for use to seal acoustic tubes in carriers according to the invention. Those of ordinary skill will recognize that such end blocks can be solid or can be formed with plugs. In addition, individual plus can be used in place of an end block. 
   Those of ordinary skill will recognize that the invention can take numerous forms and can be applied to any system which requires transporting acoustic pulses. Such systems include, but are not limited to, event counters, such as traffic counters. In such systems it may be desirable to form the carrier segment in the shape of a ramp to facilitate vehicle travel onto and off of the carrier segment. Other forms of carrier segment are also possible. The invention can be supplied as a finished manufactured unit or can be supplied as parts that can be assembled on site for a custom application. A system according to the invention can be supplied in kit form, for example, with parts such as a carrier, pneumatic tubes and acoustic pulse carrier tubes. For example, desired lengths of carrier, pneumatic tube and acoustic pulse carrier tubes can be cut from spools of such material. An optional cutting tool to form the required troughs can also be supplied with such a kit. 
     FIG. 13  illustrates still another optional feature according to the invention.  FIG. 13  shows a top view of carrier segment  1301  having a pneumatic pulse generator tube  1303  and an acoustic pulse tube  1305 , as well as acoustic tube slot  1307  and pneumatic tube slot  1309 . In order to facilitate connection to another carrier segment or other device, carrier segment  1301  can be formed with window or hole  1311  therein. Window  1311  provides an accessible area for a user&#39;s hands to make connections to the acoustic pulse tube  1305  and pneumatic pulse generator tube  1303 . In addition, because the window is open at the bottom, acoustic pulse tube  1305  and pneumatic tube  1303  are elevated off the surface, e.g. a road, on which the carrier segment  1301  rests. When an object strikes the carrier segment compressing the pneumatic and acoustic tubes, the open area at the bottom provides strain relief. In a traffic counting application, window  1311  would typically be placed at the traffic lane division.  FIG. 13  also shows a lifting member  1313  attached to said carrier segment to lift an end portion of said carrier segment. The lifting member shown is, for example, a wire extending through the window  1311  and forming a loop outside the carrier segment, so that the loop outside the carrier segment provides ease of lifting the carrier segment. Other suitable lifting members may also be used within the scope of the invention. 
   Those of ordinary skill will recognize that the invention can take other forms and is not limited to the specific embodiments herein and that various modifications and changes could be made to the invention without departing from the spirit and scope thereof as recited in the claims.