Abstract:
Pliers having a pair of handles and a pair of shank members have one member of a die pair for treating a workpiece on each of the shank members. The die members are attached to the inner sides of the shank members rotatably about an axis situated in the tool plane, and a follower is provided to ensure their corotation. The workpiece may be introduced into the die pair frontally or laterally, depending on the rotational position of the die pair. In one embodiment, the die members are also pivotable about axes extending at right angles to the tool plane. The pliers may be used in many applications such as crimping electrical terminals.

Description:
FIELD OF THE INVENTION 
     The present invention refers to pliers for treating work pieces in a pair of dies, and in particular to pliers for crimping contact elements such as terminal connectors or the like on the ends of electrical conductors. 
     Pliers of this kind exist for frontal as well, as for lateral insertion of the work piece in the die pair. By frontal insertion is understood insertion, from the front end of the tool, in a direction parallel to, or co-inciding with the longitudinal extension of the tool body and/or the handles, i.e., along the tool plane. By &#34;tool plane&#34; is understood the plane in which the handles lie and move, and in which also the die movement takes place. 
     By lateral insertion is understood insertion in a direction at right angles to the said longitudinal extension, e.g., at right angles to the tool plane. 
     Experience has proven that approximately one half of the users prefer the first mentioned manner of insertion, and the other half prefer the last mentioned manner of insertion, or that in approximately one half of all applications call for use of the one manner, and in the other half the other manner is preferred. 
     In another aspect, pliers may be divided into a category of &#34;scissors-like&#34;, where the carriers of the dies or jaws perform a scissors-like pivotal movement, and a category of &#34;vice-like&#34;, where said members perform a parallel movement. The present invention is applicable to both of said types. 
     BACKGROUND OF THE INVENTION 
     In the published German patent application Ser. No. 2,928,117 are described pliers of the scissors type which comprise a pair of hinged-together members having a rear handle portion and a front shank portion, and a pair of hinged-together flat, elongated working jaws, each with a rearward extension beyond the hinge point. The pair of jaws is with one of the rearward extensions mounted on the outer side of one of the shank portions so as to be rotatable about an axis lying in the tool plane, so that the whole pair of jaws may be swung out of the tool plane. 
     For transferring the movement of the other shank portion to the other jaw, a driving rod is slidably mounted between these two members, passing through holes in the other jaw extension and in the other shank portion. 
     The purpose of the rotatable mounting of the pair of jaws is, however, not to enable the option between frontal and lateral introduction of the work piece, but to enable adjustment of the angle between the tool plane and the jaws. 
     A pair of jaws mounted on the outside of one of the shank portions embodies a structure which considerably protrudes beyond the outline of a conventional pair of pliers, i.e., occupies additional space. The jaws, particularly when swung out of the tool plane, cannot affect the work piece with as high a thrust as when the work piece is located between two shank members. High thrust is however needed on occasion, e.g., for crimping certain electrical connectors. 
     In a sales catalog entitled &#34;Rema Press-Technik&#34; of the German firm of Rema Lipprandt GmbH &amp; Co KG, Bonn, are shown compression tongues of the vice type which have no shank members and in which the die members are mounted in a yoke member so as to be rotatable relative to the handles about an axis extending in the tool plane. 
     The tool enables application of a high thrust on the work piece, and the work piece may be introduced into the tool from any arbitrary lateral direction, but not frontally. 
     OBJECT OF THE INVENTION 
     It is an object of the present invention to provide pliers enabling optionally frontal or lateral feeding, not occupying more space than conventional pliers of comparable size, and in which the work piece may be affected with the same high thrust as in conventional pliers of comparable size. 
     Thus the user may select the manner of working which appears to him most suitable for a given task (be it connector crimping) without the need to procure, and possibly to carry to an outward job, two different pairs of pliers. 
     SUMMARY OF THE INVENTION 
     This object, and others which will become apparent hereinafter, are attained with pliers for lateral and frontal introduction of work pieces to be treated in a pair of dies, which comprise in combination: 
     a pair of handles extending in a tool plane; 
     a pair of shank members operatively connected to said handles for moving one relative another between a position of maximum spacement and a position of minimum spacement, each shank member having a free end and an inner side turned toward the other shank member; 
     a pair of co-operating die members, each die member being in the region of the said free end attached to the inner side of one of the shank members so as to be rotatable about an axis situated in the tool plane; 
     a follower means for ensuring corresponding rotation of both die members without impeding their relative movement, and comprising two co-operating parts, each one located on one of the die members, 
     so that the die pair may be turned into a selected rotational position, inclusive of the position for introducing the work piece frontally from the said free ends, and the position for introducing the work piece laterally. 
     In pliers of the scissors-type, where each die member is pivotable about a pivot axis extending at right angles to the tool plane, a truing-up means ensures parallelity of the two die members during their pivotal movement. Said truing means may be embodied by the follower means, which thus fills a double function. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects will be better understood from the following, reference being made to the accompanying drawing, in which: 
     FIG. 1A is a lateral view of the pliers according to the invention in condition for lateral introduction of the work piece, 
     FIG. 1B is a lateral view of the pliers of FIG. 1A in condition for frontal introduction of the work piece, 
     FIG. 2 shows at a larger scale a somewhat modified embodiment of the upper die member of FIG. 1, 
     FIG. 3 shows at the same scale as FIG. 2 the corresponding lower die member, 
     FIG. 4 shows in a perspective view at a still larger scale a holder-insert for the die members of FIGS. 2 and 3, and 
     FIG. 5 is a plane view at the scale of FIG. 1 of the front part of the pliers of FIG. 1 with the holder-insert of FIG. 4. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The pliers 1 of FIG. 1 are provided with two shank members 12, 22 and two handles 11, 21. The shank member 12 and the handle 11 are united into a rigid tool body 10. The handle 21 is by means of a pivot pin 23 pivotally attached to the shank member 22, more precisely to a rear extension 22&#39; thereof. The two handles 11, 21 and the two shank members 12, 22 lie in a tool plane defined by the drawing plane of FIG. 1. 
     The shank member 22 is pivotally attached to the tool body 10 by a pivot pin 24 which with the aid of a stirrup 65 is resiliently mounted on the tool body 10. This manner of mounting lies outside the scope of the present invention. It will appreciated, however, that the two shank members 12, 22 are in conventional manner movable between a position of maximum mutual spacement, and a position of minimum mutual spacement. 
     According to the present invention, a lower die member 32 and an upper die member 42 are with the aid of rotational pins 35, 45 mounted on the inner sides of the shank members 12, 22 respectively in the region of their free ends for rotation about a common rotational axis D (FIGS. 2 and 3). The said inner sides are the sides or edges of one shank member which face the other shank member, while the denominations &#34;upper&#34; and &#34;lower&#34; are purely conventional for the convex and concave dies (as the whole pair of pliers may be turned up and down). 
     The rotational pins 35, 45, embodying said axis D, are in their turn pivotally mounted in the shank members 12, 22 in a manner which will be explained more detail in connection with FIGS. 4 and 5, for pivotal movement about axes S (FIG. 5). The axes S extend at right angles to the tool plane. 
     The upper die member 42 has a substantially rectangular (FIG. 5) base plate 43, from one side of which (the lower one in the drawing) protrudes a convex die means 44. From the opposite side protrudes the said rotational pin 45 which provides the rotational mounting of the upper die member 42 in the shank member 22, and which as pin 45&#39; is more clearly shown in FIG. 2. 
     The lower die member 32 has a base plate 33 with identical plane view shape as the base plate 43, and from one side of which (the upper one in the drawing) protrudes a concave die means 34 matching the convex die means 44. From the opposite side protrudes a rotational pin 35 which is identical with the rotational pin 45, provides the rotational mounting of the lower die member 32 in the shank member 12, and as pin 34&#39; is more clearly shown in FIG. 3. 
     The upper and lower die members 32, 42 define together a die pair. 
     The upper die member 42&#39; of FIG. 2 is provided with a somewhat modified convex die means 44&#39; protruding from the lower face of the base plate 43&#39;, and with a rotational pin 45&#39; which has an axial threaded bore 45&#39;b and at least two, and preferably four depressions 45&#39;a at the surface, the purpose of which will be explained later. 
     The lower die member 32&#39; of FIG. 3 is on the upper side of the base plate 43&#39; provided with a concave die means 34&#39; matching with the convex die means 44&#39; and from the opposite lower side protrudes a rotational pin 35&#39; which is identical with the rotational pin 45&#39; having an axial threaded bore 35&#39;b and four depressions 35&#39;a at its surface. 
     In the base plate 34 or 34&#39; are further anchored two cylindrical guide rods 46 or 46&#39; which with a free length L project on the same side as the convex die means 44 or 44&#39;. 
     The base plate 43, 43&#39; is considerably thicker than the base plate 33 or 33&#39;, and for the reception of the guide rods 46, 46&#39; are there provided two openings 33&#39; with a cross-sectional shape corresponding to that of the guide rods which may freely glide therein. 
     More precisely, the arrangement is such that the guide rods 46&#39; protrude with a terminal part at their free end in the openings 33&#39;a even when the two die members 32&#39;, 42&#39; are at their maximum spacement. The length of the openings 33&#39;a corresponds at least to the said maximum spacement plus the length of the said terminal part. The thickness B (FIG. 3) of the base plate 33&#39; has obviously to be the same as the length of the openings 33&#39;a, or it may be somewhat larger than the openings, if these openings are embodied by blind holes. 
     With these dimensions, the free ends of the guide rods 46&#39; never can leave the openings 33&#39;a and never can project from the obverse face of the base plate 33&#39;. The latter circumstance could interfere with the free rotatability of the die member 32&#39;. 
     The guide rods 46, 46&#39; and their receiving openings 33&#39;a define a follower means for ensuring corresponding rotation of both die members 32&#39;, 42&#39; without impeding their to-and-fro movement. The follower means comprises two parts, viz. the rods 46&#39; and the openings 33&#39;a respectively, each of which is arranged on different die member. 
     All four corners of the rectangular base plates 33, 33&#39;, 43, 43&#39; may be bevelled, as best seen in FIG. 5, and the two guide rods 46&#39; and their receiving openings 33&#39;a are preferably located in the region of two diametrically opposed corners. The follower means may also have a different construction, and may be embodied by a single rod and a single opening with non-circular cross-section. 
     The pliers 1, i.e., the tool body 10 as well as the shank member 22, are in a per se known manner built-up of two parallel side plates such as 22a, 22b in FIG. 5 which are held together by bolts such as 22&#34; and spaced one from another by spacer sleeves such as 22&#34;a, so that a void space Z is obtained between the side plates. 
     In a preferred embodiment of the invention, the rotational pins 35, 35&#39;, 45, 45&#39; are accommodated in the void space Z in the front part of the two shank members 12, 22 with the aid of holder-inserts 50 according to FIG. 4, which preferably, but not necessarily, are made of plastics. 
     The holder-inserts 50 are substantially U-shaped with two leg parts 50a, 50b and a bridge part 50c. The legs are tapered at their free ends and are at their inner faces provided with opposite recesses 50a&#39;, 50b&#39; which together define a cylindrical bearing means with a radius corresponding to the cross-sectional radius of the rotational pins 35, 35&#39;, 45, 45&#39;. 
     The legs 50a, 50b are further at their outer faces, in the region where the recesses 50a&#39;, 50b&#39; are located at the inner faces, provided with short, protruding axle stumps 50a&#34;, 50b&#34; having a length in the order of magnitude of the thickness A (FIG. 5) of the side plates 22a, 22b. In the side plates 22a, 22b (and in the side plates of the shank member 12) are mounting openings 12a&#39;, 22a&#39; provided for the said axle stumps 50a&#34;, 50b&#34;. These axle stumps embody the pivot axis S of the respective die member 32, 42. 
     It will be realized that the above mentioned follower means 33&#39;a, 46&#39;, ensuring invariable mutual rotational position (about the axes D) of the two die members, at the same time ensures their mutually parallel position. The follower means defines thus also a truing-up means for ensuring constant parallelity of the two die members under their pivotal movements. In principle, however, even separate following and truing-up means are conceivable. 
     The assembly of the tool may proceed as follows. The axle stumps 50a&#34;, 50b&#34; of the holder-inserts 50 are inserted into the mounting openings 12a&#39;, 22a&#39; in the side plates 22a, 22b by slightly compressing the leg parts 50a, 50b. Inserts made of non-resilient material, such as metal, not allowing compression, are inserted before the side plates are affixed to one another. Thereupon are the rotational pins 35, 35&#39;, 45, 45&#39;, which embody the rotational axes D of the two die members 32, 42, introduced into the recesses 50a&#39;, 50b&#39;. 
     The rotational pins 35 etc. are as long as the legs 50a, 50b are broad (breadth G, FIG. 4), and washers 52 are affixed to their free ends by means of screws screwed-in into the threaded axial openings 35&#39;b, 45&#39;b. The diameter F of the washers 52 is smaller than the spacement C of the inner faces of the two side plates 22a, 22b, and larger than the diameter of the cylindrical bearing means defined by the two recess 50&#39;a, 50&#39;b. The die members 32, 42 are thus secured in their respective holder-inserts 50. 
     In the space between the two leg parts 50a, 50b, the bridge part 50c, and the rotational pin 35 etc. in the holder-in-sert 50 is an engagement means 53 of the drop-in-pin-type provided for temporarily locking the die members in a selected rotational position. 
     The said means comprises a resiliently mounted element such as a spring-loaded ball etc. for engagement with any of the depressions 35&#39;a, 45&#39;a on the rotational pin 35 etc. Consequently, the die pair 32, 42; 43&#39;, 42&#39; may be in arbitrary direction (clockwise or counter-clockwise) transferred from the position of FIG. 1A for lateral feed into the position of FIG. 1B for frontal feed of a work piece (and, without locking, also in any intermediate position). 
     As co-rotation of the two die members 32, 42 about the axis D is ensured by the follower means, the said engagement means 35&#39;a, 53, and particularly the part 53 thereof, may be provided only at one of the two die members. 
     An engagement means may also be arranged in some other location, e.g. on adjacent faces of the shank and die members, or it may be omitted altogether. 
     It will be appreciated that when the present invention is applied to pliers with a parallel movement of the shank members, the die members 32 etc. need not be pivotable about the axes S, and thus can be mounted in the respective shank members only for rotation about the axis D. A follower means such as 33&#39;a, 46&#39; will, however, still be needed to ensure co-rotation of the two die members. 
     The die members may also, in a known manner, comprise several die means, i.e. several die pairs for work pieces of different sizes may be provided on the two die members. 
     The invention is of course also applicable to pliers where both shank members are rigidly connected to the respective handle, or where both shank members are pivotally connected to the respective handle.