Patent Publication Number: US-6220124-B1

Title: Fire hydrant wrench

Description:
FIELD OF THE INVENTION 
     The present invention relates to wrenches, and more particularly relates to wrenches adapted for rapid use on fire hydrant fixtures. 
     BACKGROUND AND SUMMARY OF THE INVENTION 
     Wrenches especially adapted for use on fire hydrants have been the subject of patents for many years. An example is detailed in U.S. Pat. No. 4,690,019, a simplified version of which is illustrated in FIG.  1 . 
     The illustrated wrench  10  includes a head  12  and a handle  14 . An end  16  of the handle is fashioned with helical threads  18  designed to mate with corresponding threads in a base end  20  of the head. 
     In use, a firefighter must unthread the handle  14  from the head  12  enough to accommodate the fire hydrant fixture (e.g. a five-sided bolt head) in an opening  22 . Then the firefighter must thread the handle back into the head in order to grip the fixture in the opening  22  prior to turning. This is a time-consuming sequence of operations. While in many contexts “time is money,” in case of fire, time can be a matter of life or death. 
     The inherently slow unthread/thread operation of prior art wrenches is not their only drawback. Another is the time that can be lost fumbling with a wrench that falls off a hydrant. Due to the urgency of time, the firefighter typically does not thread the handle into the head to tightly grip the hydrant fixture. Instead, the handle is loosely coupled to the fixture—tightened only enough to avoid the wrench head from idly spinning around the fixture when the firefighter applies rotating torque. When the firefighter lets go of the wrench, the loose coupling often permits the wrench to fall off the hydrant onto the ground. 
     In accordance with an illustrative embodiment of the present invention, the foregoin, drawbacks of the prior art are overcome. 
     According to one aspect of the invention, a fire hydrant wrench is provided with a “chatter thread” arrangement that allows the firefighter to avoid much, if not all, of the handle-turning required in the prior art to attach a wrench to a hydrant. 
     According to another aspect of the invention, a fire hydrant wrench is provided with a release trigger that permits the wrench to be quickly disengaged from a hydrant. 
     According to another aspect of the invention, a fire hydrant wrench is provided with reversible means (e.g. gripper teeth) tending to prevent even a loosely coupled wrench from falling off a fire hydrant. 
     The foregoing and other features and advantages of the present invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a prior art fire hydrant wrench. 
     FIG. 2 shows a fire hydrant wrench according to one embodiment of the present invention in an “open” configuration. 
     FIG. 3 is like FIG. 2, but shows the wrench after the handle has been moved into the head (e.g. to couple to a fire hydrant fixture). 
     FIG. 4 is a detail showing the mounting of a spring in the FIG. 2 embodiment. 
     FIG. 5 shows a quick-release trigger used in the chatter-thread mechanism of the wrench of FIGS. 2-4. 
     FIG. 6 shows one of two gripping teeth used in the wrench of FIGS. 2-4. 
     FIG. 7 shows a retaining cap used in the wrench of FIGS. 2-4. 
     FIG. 8 shows a handle used in the wrench of FIGS. 2-4. 
     FIG. 9 shows a steamer port head that can be used in a first alternative embodiment. 
     FIG. 10 shows a hose tool head that can be used in a second alternative embodiment. 
     FIG. 11 is a side view of the hose tool head of FIG.  10 . 
     FIG. 12 shows a colored rubber handle cover used in the wrench of FIG. 2-4. 
     FIGS. 13 a-e  are additional views of the quick release trigger of FIG.  5 . 
     FIGS. 14 a-c  are additional views of the gripping tooth shown in FIG.  6 . 
     FIGS. 15 a-e  show further details of the illustrated head. 
     FIG. 16 shows an alternative handle that is not as extensively threaded as the handle of FIG.  8 . 
    
    
     PREFERRED EMBODIMENT 
     Referring to FIGS. 2-15, a preferred embodiment  30  of the present invention includes an elongate handle  32  and a head  34 . The handle  32  is similar to handles used in the prior art, including helical threads  33  (FIG. 8) cut at one end  31  and having a longitudinal axis  32   a  (see FIG.  16 ). A cap  37  is mounted on this end and provides a flat edge to urge against a fire hydrant fixture (e.g. a bolt or valve operating stem). 
     The opposite end  36  of the handle is brightly colored to facilitate location of the wrench in tall grass or under adverse lighting conditions. One way of providing the bright coloring is by a plastic tube  38  that encases the end  36  of the handle. The tube can be colored hunter orange, or other luminescent color, and can be heat-shrunk in place on the metal of the handle  32 . Alternatively, the bright coloring can be provided by other known means including painting. 
     The head  34  has a principal, or central, plane  34   a  substantially parallel to longitudinal axis  32   a  of the handle (see FIGS. 15 b  and  15   c ) and includes several internal faces  35  defining an opening  39  for receiving a hydrant fixture. A base end  40  of the head has a passageway  41  into which the threaded end  31  of the handle  32  passes, as in the prior art. However, the passageway  41  is not threaded. 
     To secure the handle in the passageway  41  of the head  34 , the wrench is provided with a chatter thread arrangement. This arrangement includes a pivotally-mounted member  43  having a radiused surface  44  that is cut with threads and urged, by a spring  48 , against the threads of the handle. (This radius spans an arc of about 36 degrees.) The threads on this radiused surface are sized and spaced to engage those on the handle. However, the pivot pin  46  is positioned relative to the threaded surface  44  so that this member  43  pivots slightly out of the way when the threaded end  31  of the handle is pushed into the head  34 . The threads on the radiused surface  44  of member  43  “chatter” against the passing threads  33  of the inserted handle, giving the structure its name. If the pushing force is removed, the member  43  is spring-biased towards the handle so that its threads on surface  44  engage the handle threads. 
     In the illustrated arrangement, member  43  is provided with a trigger protrusion  42  that serves as a quick release feature. When a user presses this protrusion inwardly, it causes the threaded surface  44  of member  43  (hereafter “trigger threads”) to move away from and disengage the threads  33  on the handle  32 , permitting free sliding movement of the handle. 
     In use, the firefighter first operates the quick release trigger and withdraws the handle from the head to the extent possible. (Cap  37  prevents the handle from being fully withdrawn.) The wrench is then placed so that the hydrant fixture is received within the head opening  39 . To close the wrench, the firefighter simply pushes the handle into the head. The trigger  42  may, but needn&#39;t, be operated. (If the trigger isn&#39;t operated, the force of the handle threads against the trigger threads causes the trigger to repeatedly chatter aside, as described above.) The handle is pushed into the head until the cap  37  abuts the hydrant fixture. At this point, the firefighter can torque the wrench to turn the hydrant fixture. Alternatively (and this is not necessary), the firefighter can first manually turn the handle to cinch the end cap  37  tightly against the fixture. (Often less than a single turn, e.g. a quarter-turn, will suffice for this purpose.) This puts the threaded end  31  of the handle under compression. Such a force causes the member  43  to pivot towards the handle, forcing the threads on the handle and trigger into tighter engagement, preventing any slippage of the handle relative to the head. 
     To release the wrench from the fixture, the firefighter simply squeezes the trigger, disengaging its threads from the handle threads and permitting the handle to be withdrawn from the head. (If the firefighter cinched the cap  37  tightly against the fixture, the handle must first be counter-rotated slightly to remove the compressive force from end  31  of the handle before the trigger can be actuated to disengage the threads.) 
     Uncharacteristically for fire hydrant wrenches, the threads in the illustrated embodiment are finely spaced (e.g. 16 per inch, versus 10 or less per inch in the prior art). In the prior art, coarse thread pitch is desired because the handle then moves more quickly into engagement with the hydrant fixture when rotated. However, the fine pitch in the illustrated embodiment permits a finer positioning of the cap end relative to hydrant fixture when the handle is simply pressed (rather than threaded) into engagement. 
     Desirably, head  34  also includes one or more gripping teeth  58  (two teeth in the illustrated embodiment) fastened inside the opening  39  by recessed bolts  54 . The teeth serve as faces  35  of the opening  39 . The teeth, more particularly shown in FIGS. 6 and 14, are provided with sharp edges  60 . These edges are oriented parallel to the principal plane  34   a  of the head, and serve to bind and engage the metal of the hydrant fixture. These edges  60  are angled out so that they act to prevent the wrench from falling off the hydrant feature, even if the wrench is only loosely coupled to the feature. (In the illustrated embodiment, the gripping teeth each includes a portion  62  in the shape of a non-rectangular trapezoid, although other shapes can naturally be used. As best illustrated in FIG. 14 c  contiguous faces of edge portions  60  have an included angle less than 90°.) The arrangement of the two edges assures at least one will grip, regardless of how the wrench is oriented (i.e. the arrangement is reversible). 
     The teeth  58  are formed of a relatively hard metal (e.g. A-2 tool steel). The remainder of the head is fashioned (e.g, forged) of more conventional steel (e.g. 8630 cast steel). The handle can be formed by various known techniques. 
     From the foregoing, it will be recognized that the preferred embodiment overcomes various drawbacks of the prior art. The chatter thread arrangement speeds use of the wrench to operate a fire hydrant. The quick-release trigger speeds disengagement of the wrench from a hydrant, and can be used to speed engagement as well. The gripping teeth help prevent the wrench from inadvertently dropping from the hydrant. 
     Having described and illustrated the principles of my invention with reference to a preferred embodiment, it will be apparent that the invention can be modified in arrangement and detail without departing from such principles. 
     For example, in alternative embodiments, the threaded end of the handle may not be fully threaded. For example, the top-most and bottom-most portions of the threading shown in the figures can be omitted, since the trigger threads never engage the handle in those regions, and—in the case of the top-most threading—it accelerates wear on the threads of the trigger. Moreover, having the bottom part of this region unthreaded avoids wear when the handle is subjected to a torquing force (which might deform threads near where the handle enters the head). 
     In other embodiments, the illustrated chatter-thread arrangement can be replaced by other known arrangements that perform similar functions (e.g. other sliding ratchet arrangements). 
     In still other embodiments, the quick release trigger can be constructed, or mounted, differently than shown. 
     In yet other embodiments, the threads on the handle may have other pitches, e.g. 12/inch, 14/inch, more than 16/inch, etc. 
     In still other embodiments, the head of the wrench may be provided with various utilitarian features, such as the steamer port and hose tools shown in FIGS. 9-11. 
     In yet other alternative embodiments, the gripping teeth can be integrally formed with the head, rather than removably attached thereto. 
     In yet other alternative embodiments, the wrench can be provided with certain of the disclosed features without others (e.g. a chatter thread arrangement without a quick-release trigger feature; gripper teeth without a chatter thread arrangement, etc.). 
     In still other embodiments, advantageous features shown in other prior art hydrant wrenches (e.g. those illustrated in U.S. Pat. Nos. 5,255,576 and 4,690,019, incorporated by reference) can be used in conjunction with the novel features of the preferred embodiment. 
     Many other such variations will be apparent to the artisans in the tool and/or hydrant arts. 
     In view of the wide variety of embodiments in which the principles of my invention can be employed, it will be recognized that the illustrated embodiment is exemplary only and should not be understood as limiting the scope of my invention. Rather, I claim as my invention all such embodiments as may come within the scope and spirit of the following claims, and equivalents thereto.