Abstract:
Pliers of specialized construction for depressing the retaining spring of an electrical connector terminal include a rigid thin blade extending forwardly of the jaws of the pliers. A recess, disposed in the blade, is positioned and shaped in a manner to accommodate a retaining shoulder that is generally positioned in front of the spring and would otherwise block access of the pliers to the spring.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to specialized pliers for removing spring-secured electrical connectors from a housing. 
     2. Description of the Prior Art 
     Battery-operated industrial fork lift trucks are extensively used for the handling of heavy loads in factory, warehouse and other commercial applications. The battery-operated lift trucks are preferred over fuel-driven trucks because they are quieter in operation and do not emit combustion gases which would adversely affect an indoor environment. 
     The batteries of such electrically driven lift trucks require frequent recharging. To facilitate the connection of the batteries to a suitable electrical DC power source, receiving connector terminals are provided on the truck and are adapted to interact with feed connector terminals associated with the power source. The receiving connector terminals are generally secured by a protective housing which maintains the terminals in parallel, spaced apart relationship. In particularly popular embodiments, the receiving terminals have an elongated flattened configuration provided with an engagement hump, and are spring-urged toward a latching position. The feed terminals from the power source are similarly secured within a protective housing and spaced apart to match the spacing of the receiving terminals. The feed terminals have a flattened configuration with an engaging hump comparable to the receiving terminals and are also spring-urged toward a latching position. One set of terminals, whether the feed or receiving terminals is caused to protrude from a male-designated housing and adapted to enter a female-configured housing wherein the opposing interactive terminals are recessed within the housing. 
     In view of the aforesaid construction, the mating of the feed terminals with the receiving terminals is quickly and easily accomplished merely by pushing one housing toward the other axially with respect to the direction of elongation of the terminals. Such action brings the opposed terminals into secure engagement with properly maintained polarity. By virtue of the interlocking effect achieved by the interactive engagement humps and the springs which force the terminals together as a latched state, the terminals resist inadvertent separation. 
     In the course of prolonged use, the receiving and feed connector terminals must be removed from their housings for servicing. It has been found, however, that such removal is extremely difficult because of the aforesaid springs which secure the terminals in place. Removal of terminals from female-configured housings is particularly difficult because, not only must said spring be depressed to facilitate removal, but it is difficult to reach into the housing in order to access the spring. 
     Various types of specialized hand tools have earlier been disclosed for coping with difficult manipulative tasks. For example, plier-type tools designed for handling spring components are disclosed in U.S. Pat. Nos. 4,697,483; 5,212,859; 5,209,143 and 5,590,573. However, the tools of each of said Patents involve motions which apply force against two extremities of a spring in order to achieve movement or configurational change of the spring. U.S. Pat. Nos. 4,353,273 and 5,209,143 disclose pliers of substantially conventional design having opposing jaws which are modified to accomplish very specific tasks. None of the aforesaid Patents disclose pliers specifically designed to force an otherwise inaccessible spring against a fixed feature of a multicomponent structure in order to permit sliding release of a component otherwise secured by said spring. 
     It is accordingly an object of the present invention to provide a hand tool for facilitating the release of a spring-held electrical terminal from a connector housing. 
     It is a further object of this invention to provide a hand tool of the foregoing object in the form of pliers of substantially conventional design but with a specially modified jaw configuration. 
     It is another object of the present invention to provide a hand tool of the aforesaid nature wherein said modified jaw configuration permits depression of a holding spring against a fixed feature of said housing. 
     It is a still further object of this invention to provide pliers of the aforesaid nature of simple, durable construction amenable to low cost manufacture. 
     These objects and other objects and advantages of the invention will be apparent from the following description. 
     SUMMARY OF THE INVENTION 
     The above and other beneficial objects and advantages are accomplished in accordance with the present invention by pliers of the type comprised of first and second elongated members connected at a pivot axis to define interactive first and second jaws and opposed handle portions arranged such that said jaws are brought together when said handle portions are brought to their position of closest approach within an action plane orthogonal to said pivot axis. Said first jaw, having a substantially flat gripping surface, extends to a forward end located a distance from said pivot axis which is generally considered typical of pliers. Said second jaw extends to a front end located closer to said pivot axis than the forward end of said first jaw, and having a rigid thin blade extending forwardly of said front end and positioned substantially on said action plane. Said blade extends to a leading edge located forwardly of the forward end of said first jaw, and is further provided with a gripping edge adapted to contact the gripping surface of said first jaw, and a recess located adjacent the front end of said second jaw and directed away from said gripping edge. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawing forming a part of this specification and in which similar numerals of reference indicate corresponding parts in all the figures of the drawing: 
     FIG. 1 is a sectional side view of an embodiment of a female terminal connector serviceable by the pliers of the present invention. 
     FIG. 2 is a front view of the connector of FIG.  1 . 
     FIG. 3 is a side perspective view of an embodiment of the pliers of the present invention shown in a partially open state. 
     FIG. 4 is a fragmentary side view of the pliers of FIG. 3 shown in its closed state in operative engagement with the connector of FIG.  1 . 
     FIG. 5 is a front view of the embodiment of FIG.  4 . 
     FIG. 6 is a fragmentary top view of the pliers of FIG.  4 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to FIGS. 1 and 2, a female electrical terminal connector  10  is shown comprised of a plastic housing  11  elongated between open front and rear extremities  12  and  13 , respectively, and further bounded by top and bottom panels  14  and  15 , respectively, and side panels  16 . 
     Housing  11 , generally fabricated of plastic as a monolithic molded structure, further contains a front retaining shoulder  17  and interior abutment wall  18 . A flat spring  19 , bounded in part by opposed side edges  48 , is emplaced upon the interior surface  20  of bottom panel  15 , and extends to an upwardly biased leading extremity  21 . Two electrical terminals  22 , designated positive and negative, are disposed in separated side-by-side juxtaposition within said housing. Each terminal is comprised of a hollow rear extremity  23  adapted to receive an electrical conductor cable  50 , and a distal portion  25  having a flat contour bounded in part by opposed side edges  47  causing said distal portion to be of narrower horizontal width than the underlying spring  19 . Said distal portion further includes an upwardly raised engaging hump  26  and a downwardly turned lip  27  adapted to engage the leading extremity  21  of spring  19 . A transition zone  28 , located between rear extremity  23  and distal portion  25 , has a conically tapered surface  29  adapted to contact abutment wall  18 , thereby stabilizing the terminal with respect to forward movement. 
     By virtue of the aforesaid construction, spring  19  secures the terminals in a proper fixed position within the housing, and also enables similarly spring-biased male terminals to be inserted into locked joinder with terminals of a female-configured housing. Said construction also permits rearward sliding removal of the terminal when the leading extremity  21  of the spring is depressed. However, the construction of terminal connector  10  is such as to make it very difficult to reach inside housing  11  through front extremity  12  and depress spring  19 . It is for just such purpose that the pliers of the present invention has been invented. 
     Referring now to FIGS. 3-6, an embodiment of the pliers  31  of the present invention is shown comprised of first and second elongated members  32  and  33 , respectively, connected by pivot bolt  34  to define interactive first and second jaws  35  and  36 , respectively, and opposed handle portions  37 . The pliers are constructed such that said elongated members  32  and  33  are adapted to move in scissor-like relationship about a centered plane of action  38  orthogonally disposed to bolt  34 . In the course of said scissor-like motion, said jaws are brought together when said handle portions are brought to their position of closest approach. Such movement also defines an embracing region  50 . 
     First jaw  35 , having a substantially flat gripping surface  39  disposed orthogonally to said action plane, extends to a forward end  40  located a distance from said pivot bolt which is generally considered typical of pliers. Second jaw  36  extends to a front end  41  located closer to pivot bolt  34  than the forward end  40  of said first jaw. A rigid thin blade  42  extends forwardly from said second jaw substantially upon said action plane. Blade  42  extends to a leading surface  43  located forwardly of forward end  40  of said first jaw, and is further bounded by outer surface  44  and gripping surface  45  adapted to contact gripping surface  39  of said first jaw. A recess  46  is formed in blade  42  at a location between gripping surface  45  and the front end  41  of said second jaw. Recess  46  has a mouth extremity  51  which opens onto region  50 , and a closed extremity  52  directed toward outer surface  44 . Although the exemplified embodiment of recess  46  is shown to have an arcuate configuration concavely contoured with respect to region  50 , other configurations of said recess may be employed. It is preferred however, that mouth extremity  51  is larger, measured in said action plane, than said closed extremity. Blade  42  may be either a continuous integral extension of said second jaw or may be affixed to said jaw by way of insertion into a receiving groove, followed by welded securement. 
     By virtue of this specialized construction, the pliers of this invention can be employed, as shown in FIG. 4, to reach into housing  11  and depress the leading extremity  21  of spring  19 . Such action, which permits the release of electrical terminal  22 , is achievable because blade  42  can enter the housing, and its gripping surface  45  can contact the upper surface of spring  19  where it extends laterally beyond the distal portion  25  of the terminal. Such function is permitted because recess  46  accommodates front retaining shoulder  17  when the jaws are positioned such that gripping surface  39  of said first jaw rests in abutment with bottom panel  15  beneath retaining shoulder  17 . 
     While particular examples of the present invention have been shown and described, it is apparent that changes and modifications may be made therein without departing from the invention in its broadest aspects. The aim of the appended claims, therefore, is to cover all such changes and modifications as fall within the true spirit and scope of the invention.