Patent Publication Number: US-6217253-B1

Title: Ribbon marking tool

Description:
TECHNICAL FIELD 
     This invention relates to a tool for marking the location of a buried conveyance, such as a pipe or cable. 
     BACKGROUND ART 
     Many utilities bury their pipes and cables (hereinafter, “conveyances”) underground, both for cosmetic reasons, as well as to protect such conveyances from the elements. The utility undertaking burial records the location of the burial on a map to facilitate finding the conveyance at a later time. Contractors seeking to excavate in the vicinity of a conveyance will want to know the precise location of the conveyance to avoid damage thereto. While maps may provide a general indication of the location of the buried conveyance, most utilities invariably will dispatch a technician to physically locate the conveyance, typically using electromagnetic signaling for this purpose. Upon physically locating the conveyance, the technician will traditionally spray a water-soluble paint on the ground above the conveyance. Depending on weather and the extent of ground traffic, such marks may last two to three days. If excavation will occur for any longer duration, the technician must replenish the previously sprayed markings, often necessitating another visit to the job site. 
     In some instances, spray painting the markings may not suffice, requiring a more permanent method of indicating the location of the buried conveyance. To that end, utilities have resorted to placing metal flags at spaced intervals along the path of the buried conveyance. While the flags are more durable than the sprayed markings, the use of flags incurs disadvantages as well. Generally, the flags are simply pushed into the ground, allowing relatively easy removal and transfer to a different location. Unless the excavating contractor is specifically aware of the original location of the flags, the contractor may simply not notice any change in their location and presume it is safe to excavate in absence of the flags when in fact, buried conveyances exist. Moreover after deployment, the technician must remove the flags to avoid damage to lawn mowers and other similar equipment. 
     Thus, there is a need for a technique that provides a more permanent marking method to identify buried conveyances. 
     BRIEF SUMMARY OF THE INVENTION 
     Briefly, the present invention concerns a marking tool for dispensing a length of warning tape and for securing the tape to the ground above a buried conveyance. The tool includes a housing within which a roll of warning tape is mounted for rotation. A dispensing mechanism feeds the tape through the housing along a path overlying an opening in the housing in communication with the ground. A staple-driving mechanism lies within the housing opposite the opening but is separated therefrom by the length of tape fed by the dispensing mechanism. A cutting mechanism lies along the path of tape travel for severing the tape once the staple driving mechanism drives a staple through the tape to secure it to the ground. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 depicts a ribbon marking tool in accordance with the invention for use by an operator for dispensing a length of warning tape above a buried utility conveyance; 
     FIG. 2 depicts a portion of the tool of FIG. 1 showing the tool handle; 
     FIG. 3 is block diagram of the mechanism within the tool of FIG. 1 for dispensing, stapling and cutting the warning tape; and 
     FIG. 4 shows an alternate preferred embodiment of a portion of the mechanism for dispensing, stapling and cutting the warning tape. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 shows a ribbon-marking tool  10  in accordance with the invention for use by a operator  12  to dispense a length of flexible warning tape  14  along the ground  15  above a buried utility conveyance  16 , such as a pipe or cable. In practice, the warning tape  14 , typically made from plastic or MYLAR, carries indicia  18 , in the form of a message warning of the existence of the buried conveyance  16 . For example, the indicia  18  typically includes both a warning message, such as “WARNING—BURIED UNDERGROUND CONVEYANCE”, and also include the identity of the utility responsible for the conveyance, as well as a telephone number or address for contacting the utility, although the later is not always necessary. 
     The ribbon-marking tool  10  of the invention comprises a housing  20  of a material such as plastic or aluminum. At a first or upper end of the housing  10  is a handle  22  which, as best illustrated in FIG. 2, includes a first pistol grip  24  for engagement by a first hand  25  of the operator  12  of FIG.  1 . The grip  24  carries a trigger switch  26 , which, as described hereinafter, serves to control the dispensing, stapling and cutting of the warning tape  14  by the tool  10 . Additionally, the handle  22  includes a second grip  28  in the form of a foam rubber collar for engagement by the second hand  29  of the operator  12  of FIG.  1 . 
     As best seen in FIG. 1, the housing  20  includes an enlarged lower portion  30  whose interior is accessible through a hinged door  31  to allow entry into the housing to a mechanism  32  (see FIG. 3) that serves to dispense, staple and cut the warning tape  14 . In the illustrated embodiment, the door  31  has a circular opening  34  sized to receive a roll  36  on which a length of the warning tape  14  is wound. At the center of the opening  34  is a spindle  38  on which the warning tape roll  36  rotates to permit the tape to feed into the mechanism  32  of FIG.  3 . Note that the opening  34  for receiving the tape roll  36  could lie in the lower housing portion  30  adjacent to the door  31 , rather than extend through the door itself. 
     Referring to FIG. 3, the mechanism  32  for dispensing, stapling and cutting the warning tape  14  includes first upper and lower warning tape engagement means  40  and  42 , respectively. In the illustrated embodiment, the first upper and lower warning tape engagement means  40  and  42  comprise upper and lower conveyor belts for engaging the top and bottom surface, respectively, of the warning tape  14  as it is fed from the roll  36 . A motor  44  drives the conveyor belts  40  and  42  in opposite directions to advance the warning tape  14  past a window (opening)  48 , which as best shown in FIG. 1, lies in the base of the lower housing portion  30  in communication with the ground  15 . 
     Second upper and lower engagement means  50  and  52 , typically comprised of upper and lower conveyor belts, respectively, lie adjacent to the window  48  opposite the first upper and lower conveyor belts  40  and  42 , respectively. Upon actuation of the trigger switch  26 , a battery  56  powers the motor  44  to drive the first upper and lower conveyor belts  40  and  42  in opposite directions to advance the warning tape  14  across the window  48  and into engagement with the second upper and lower conveyor belts  50  and  52 . Unlike the first upper and lower conveyor belts  40  and  42  that are motor-driven, the second upper and lower conveyor belts  50  and  52  are free spinning, and simply serve to engage the free-end of the warning tape  14 , thereby maintaining the warning tape somewhat taut across the window. 
     The trigger switch  26  also couples the battery  56  to a motor-driven hammer  58  overlying the window  48  but separated therefrom by the warning tape  14 . When powered by the battery  56 , the motor-driven hammer  58  serves to drive a first staple  60  within a stack of staples  62  through that portion of the tape  14  overlying the window  48  to secure the tape to the ground  15 . A resistance heater bar  64  lies adjacent to the first upper and lower conveyor belts  40  and  42  for contacting the warning tape  14  advanced by the conveyor belts across the window  48 . The trigger switch  26  couples the heater bar  64  to the battery  56  so that upon actuation of the switch, the battery excites the heater bar, which in turn, melts the warning tape  14  to sever it from the roll  44 . 
     In operation, the operator  12  holds the tool  10  with the window  48  in the lower portion  30  of the housing  20  opposite the ground  15 . To this, end, the lower housing portion  30  typically includes a roller  64  to allow the operator  12  to roll the housing  20  along the ground  15  to maintain the window  48  in a substantially fixed relationship thereto. Once the operator  12  has positioned the tool at a location above the buried conveyance  16  of FIG. 2, the operator operates the trigger switch  26  of FIGS. 2 and 3 to actuate cause the motor-driven hammer  58  of FIG.  3 . Once actuated, the motor-driven hammer  58  drives staple  60  of FIG.  3  through the warning tape  14  and into the ground  15  of FIG. 1, thereby dislodging the free end of the warning tape from the second upper and lower conveyor belts  50  and  52 . 
     With the warning tape  14  now stapled to the ground, the operator  12  will operate the trigger switch  26  of FIGS. 2 and 3 to actuate the first upper and lower conveyor belts to allow feeding of the warning tape  14  through the window  48  and on the ground  15  along the path of the buried conveyance  16  of FIG. 1 as the operator walks therealong. While as the warning tape  14  is dispensed, the operator  12  will actuate the trigger switch  26  to actuate the motor-driven hammer  58  to drive an additional staple  60  into the tape. Once a sufficient length of tape  14  is dispensed, the operator  12  will actuate the trigger switch  26  and actuate the heater bar  64  to cut the warning tape  14  proximate the additional staple. 
     Rather that utilize the first upper and lower conveyor belts  40  and  42  to feed the warning tape  14  past the window, a first pair of laterally spaced sprocket wheels  66  and  68 , driven by the motor  44  in unison, could be substituted, provided the warning tape  14  includes first and second sprocket-engaging apertures  70  and  72  for engaging the sprocket wheels. Similarly, a second pair of laterally spaced, free spinning sprocket wheels could be substituted for the upper and lower conveyor belts  50  and  52 . A pair of laterally spaced guides  78  and  80  directs the warning tape  14  from the first pair of sprocket wheels  66  to the second pair of sprocket wheels  74  and  76 . 
     The warning tape feed arrangement of FIG. 4 operates to feed the warning tape  14  past the window  48  once the motor  44  is actuated to drive the first pair of sprocket wheels  66  and  68  so they engage the sprocket-engaging apertures  70  and  72 . As the warning tape  14  advances, the guides  78  and  80  feed the tape into warning tape into engagement with the sprocket wheels  74  and  76 . 
     The foregoing describes a ribbon marking for dispensing a length of warning tape to marking the location of a buried conveyance, such as a pipe or cable.