Patent Publication Number: US-6708587-B1

Title: Vise-grip or expanding pliers

Description:
The invention relates to clamping or expanding pliers having two pliers arms which are connected to one another in the manner of a scissors articulation and form, at one end, handle sections and, at the other end, clamping sections which can be moved toward one another when the handles are actuated, it being possible for the two pliers arms to be latched in clamping positions with the clamping sections in a diversity of spaced apart positions. 
     From the Gödde catalog 1989, page 531, there is known clamping pliers for installation or assembly purposes, as also find use in the field of surgery. The clamping force is based on the restorable deformability of the pliers legs. The blades are thus of relatively narrow configuration, as are likewise the relatively long pliers jaws. In practice, they are similar to tweezers arms. The respective clamping position can be fixed by a releasable locking clamp. Corresponding tooth-like latching protrusions are located between the blades. The release operation requires the pliers arms to be twisted. This may result in the pliers jaws being offset in relation to one another. 
     Also known are stamped formations on cable cutters and pruning shears (U.S. Pat. No. 1,454,917, U.S. Pat. No. 4,062,218, GB patent specification 1 056 176) by way of which a toothed segment and a disengageable catch are disposed such that the pliers arms remain free from twisting. These solutions, however, require high-outlay gear mechanisms. 
     It is an object of the invention for clamping pliers of the generic type to be kept free of twisting forces in the knuckle joint, but nevertheless to be configured more straightforwardly in structural terms. 
     This object is achieved first and foremost, in the case of clamping pliers having the features of claim  1 , by an arcuate toothed strip which is associated with one pliers arm and in the toothing formation of which there engages a catch which is associated with the handle section of the other pliers arm. The arcuate toothed strip may be integrated, which reduces the number of parts. The catch is associated straightforwardly with the other pliers arm. This can take place in the spatial vicinity of the knuckle joint, so that the release can also be controlled very well in terms of ergonomics. Should the clamping pliers consist of plastics material, then, for the purposes of maximizing the wear strength, the arcuate toothed strip may consist of a relatively harder plastics material than the pliers arms themselves. The arcuate toothed strip is in advantageous manner positioned in a recess of a pliers arm. In structural terms, this is such that the arcuate toothed strip is pinned to the pliers arm by means of the scissors-articulation pin and is supported thereon. It is further proposed for the clamping sections of the pliers arms to carry tiltable clamping jaws at the ends. This makes it possible, in each expanded position, for a plate-like object to be gripped in a plane-parallel manner on both sides. A further contribution of the invention is that the one pliers arm provides an opening through which the other pliers arm is inserted, this achieving the so-called inserted type of articulation for the tool. This solution is further characterized in that the inwardly-located, that is to say through-engaging pliers arm, carries the arcuate toothed strip. The solution proves favorable in terms of actuation in that the catch forms an actuating section which projects into the handle section. The actuating section is in advantageous manner located in a window of the handle section. The arrangement by which the handle section has a U-shaped cross-section, in the cavity of which the catch is rotatably located, proves favorable in structural terms and has a material-saving effect. The handle section itself has a bearing pin which passes through the cavity and is intended for the catch. It is advantageous then that the pliers arms are mounted resiliently in the expanding direction of the clamping jaws. With release of the catch, the clamping pliers thus always spring into their open position. Furthermore, a measure of even independent importance consists in the clamping force of the pliers being greater than the force which is necessary for release of the catch. This results in immediate release and opening of the clamping pliers without the catch-equipped pliers arm having to be gripped for the purpose. It is further provided for the catch to be acted upon by one arm of the expanding spring. The expanding spring thus has a double function; it functions as catch spring and as restoring spring for the clamping pliers. The corresponding accessibility in the direction of the catch is achieved by one arm of the expanding spring penetrating through a slot of the arcuate toothed strip. A further feature consists in the expanding spring being a rotary leg spring, the coil of which is secured by the scissors-articulation pin. Finally, it is also proposed for the ends of the clamping sections to provide bearing eyelets into which bearing pins of a bearing pocket of the clamping jaw project. The pockets are accessible so that such clamping jaws can be exchanged by means of an auxiliary tool, for example if specific gripping profiles are necessary. All that is required is for the clamping jaws to be exchanged. Finally, the situation where the clamping force is maintained by an elastic deformation of the clamping sections is also achieved. Powerful clamping, free from twisting, is present in the pivoting plane of the pliers arms. 
     An advantageous development of the clamping or expanding pliers according to the invention then consists in the catch and the actuating section being formed in two parts. This allows an intermediate function to be introduced. This is realized in that the spacing between the tooth-engagement point of the catch and toothing formation and the bearing pin for the rotatable mounting of the actuating section is shortened by a first actuation of the actuating section such that the two clamping sections are disengaged from the clamping position into a release position, the tooth engagement remaining maintained, said tooth engagement being released upon a second actuation of the actuating section. The second actuation thus no longer takes place counter to the clamping force of the tool. The first actuation requires a considerably reduced release force; the unblocking operation occurs in a “more gentle” manner. It is provided here that, upon the first actuation, catch and actuating section are pivoted toward one another and are displaced. The displacement is made possible as a result of a longitudinal slot of the catch, the bearing pin engaging through said longitudinal slot. The further means are characterized here by a disengagement pin which is associated with the actuating section, engages in an angled slot of the catch and, in the position associated with the clamping position, engages in a first slot section, which runs substantially transversely to the connecting line between tooth-engagement point and bearing pin, and, in the position associated with the release position, passes into a second slot section, which runs substantially parallel to the connecting line. The toggle-joint-like control system achieved in this way operates in a positively controlled manner: first the disengagement, then parallel displacement of the disengagement pin in the last-mentioned, that is to say second, slot section. In this case, the second slot section runs in the same direction as the longitudinal slot. Catch and actuating section are acted upon by the same arm of the expanding spring. This acts in engagement-securing manner on the ratchet mechanism. 
    
    
     The subject-matter of the invention is explained in more detail hereinbelow with reference to two exemplary embodiments illustrated in the drawings, in which: 
     FIG. 1 shows the clamping pliers, with the pliers mouth open, in perspective illustration, according to the first exemplary embodiment, 
     FIG. 2 shows this position of the clamping pliers in side view, 
     FIG. 3 shows the section along line III—III in FIG. 2, 
     FIG. 4 shows the section along line IV—IV in FIG. 2, 
     FIG. 5 shows the clamping pliers in side view, but with the mouth closed, 
     FIG. 6 shows a side view in the direction of the right-hand side of FIG. 5, 
     FIG. 7 shows a partially cut-away side view in the direction of the left-hand side of FIG. 5, 
     FIG. 8 shows an illustration corresponding to FIG. 2, but with knuckle-joint region and the catch region cut away, 
     FIG. 9 shows the clamping pliers in side view, with the mouth closed, according to the second exemplary embodiment, 
     FIG. 10 shows a side view in the direction of the right-hand side of FIG. 9, 
     FIG. 11 shows a side view in the direction of the left-hand side of FIG. 9, 
     FIG. 12 shows the clamping pliers gripping an object with clamping action, to be precise in side view, 
     FIG. 13 shows the clamping pliers in a release position, 
     FIG. 14 shows the clamping pliers in a spreading/open position, 
     FIG. 15 shows the cut-away knuckle-joint region of the clamping pliers in the position according to FIG. 12, 
     FIG. 16 shows the cut-away knuckle-joint region of the clamping pliers in a preliminary position which initiates the release position, 
     FIG. 17 shows the cut-away knuckle-joint region in a position according to FIG. 13, and 
     FIG. 18 shows the cut-away knuckle-joint region of the clamping pliers in a position according to FIG.  14 . 
    
    
     The clamping pliers  1  illustrated is provided with a scissors articulation, but with formation of a so-called through articulation. 
     A scissors-articulation pin  2  also helps to form the articulation. Said pin passes through congruently located eyelets  3  in the crossover region of two pliers arms  4 ,  5 . The pliers arm designated  4  is the inner, that is to say through-engagement, pliers arm. 
     The pliers arms  4 ,  5  consist of plastics material. They are produced in a material-saving cross-sectional form, that is to say they are preferably hollowed to be open on the mouth and handle inner sides. 
     The pliers arm  4  provides a handle section  6 , serving for handle actuation, and has a clamping section  7 , which effects the gripping of an object. In the same way, the pliers arm  5 , through which the pliers arm  4  engages, has a corresponding handle section  8  and a clamping section  9 . In the region of the knuckle joint G of the pliers arms  4 ,  5 , which are connected to one another in the manner of a scissors articulation, a change in the direction of the sections  6 - 9  takes place, such that the pliers arms  4 ,  5  form, in practice, a Z-shaped outline. This results in a considerable widening between the changing-over parts of the pliers arms  4 ,  5 . 
     The pliers arms  4 ,  5  can be latched in a clamping position. This relates both to the maximum closure position of the pliers mouth  10  of the clamping pliers  1  and also to intermediate positions up to the maximum stop-defined expanded position of the mouth-side clamping sections  7 ,  9 . For latching in this respect, there serves an arcuate toothed strip  11 . The toothing formation  12  of the latter is sawtooth-like. The arc has a radius R, the radius point of which forms the geometrical axis of the scissors-articulation pin  2 . 
     The arcuate toothed strip  11  is associated with one pliers arm  4 . It may be formed integrally therewith. It is however, preferably provided that the arcuate toothed strip  11  consists of a harder plastics material than the pliers arms  4 ,  5 . In such a case, preference is given to multi-part construction. 
     A catch  13  interacts with the toothing formation  12 . The catch is secured in the region of the handle section  8  of the pliers arm  5 , through which the pliers arm  4  engages, but is accommodated such that it is easily accessible for actuation. The catch  13  has the corresponding mating toothing formation  14 . Both the steep flank of the toothing formation  12  and also that of the mating toothing formation  14  is directed toward the radius point of the scissors-articulation pin  2 . The respective rear side of the teeth presents a sloping configuration in a manner which can be seen from the illustration and is typical of sawteeth. 
     As can also be gathered from the drawing, the arcuate toothed strip  11  is located in a recess  15  of the through-engaging pliers arm  4 , said recess being in the vicinity of the knuckle joint. The segment-like strip has a contour such that securing of said strip can be effected by the scissors-articulation pin  2 , which is present in any case and thus pins the arcuate toothed strip  11  to the pliers arm  4 . For this purpose, the arcuate toothed strip  11  has an eyelet located congruently with the eyelet  3 . Furthermore, the recess is of such a contour that the segment-like arcuate toothed strip  11  is also supported on both sides of the rotary plane of the scissors articulation. It is very much enclosed. The whole arrangement is also bordered, on the broad sides, by wall sections of the through-engaging pliers arm  4  and also by those of the pliers arm  5 , the opening of which serving for the pliers arm  4  to be inserted through being designated  16 . 
     As can be gathered from FIG. 2, the catch  13  is placed at the knuckle-joint end of the handle section  8  such that an actuating section  17  projects laterally to be accessible from the outside. The actuating section is like a pushbutton. It is located in the region of a depression  18 . The latter is located on the outside of the handle section  8  and functions as the target location to be found by feel for actuating action. The entire mechanism is within the grasp of the hand and so can be easily reached. 
     The catch  13 , including the actuating section  17 , forms a double lever which is mounted such that it can be pivoted about a pin  19  in the interior of the hollow handle section  8 . The pin  19  is located on the handle inner side behind a window  20  of said handle section  8 . The window is located in the U-web of the cross-sectionally U-shaped handle section  8 , which leaves a hollow space  21 . The catch  13  has its actuation end stop on a lower window section. The tilting angle of the catch  13 , which is mounted in the manner of a rocker, is coordinated with the tooth-disengagement depth. 
     As can be seen, the catch  13  is, as it were, double-tailed. The two tails  22  and  23  are oriented in the direction of the handle end and leave a bearing recess  24  between them. This recess engages over more than half of the outer wall of the pin  19 , which is a cylindrical body, the recess forming at the same time a bearing eyelet. This establishes a securing action. Further securing means may be dispensed with. 
     The tail  23 , which is closer to the knuckle joint G, also has an additional function. This is because this tail  23  of the catch  13  is subjected to loading by an arm  25  of an expanding spring  26 . The loading takes place in the direction of the toothing formation  12 , with the effect of producing the ratchet-action engagement of the catch  13 . The other arm  27  of the expanding spring  26 , which is realized as a rotary leg spring, subjects the through-engaging pliers arm  4 , and to be more precise that end region of the handle section  6  which is in the vicinity of the knuckle joint, to loading. 
     The expanding spring  26  has a prestressing and thus acts on the clamping sections  7 ,  9  of the clamping pliers  1  such that the pliers arms  4 ,  5  are subjected to loading in the expanding direction of the clamping jaws  28 . 
     The securing of the expanding spring  26  takes place by utilizing the hollow of the coil  29  of the rotary leg spring. The scissors-articulation pin  2  of the knuckle joint G passes through said hollow. 
     Since, as far as the expanding spring  26  is concerned, there is a space requirement in relation to the arcuate toothed strip  11 , the arcuate toothed strip  11  is provided with a slot in order to accommodate the coil  29  and the arm  25 , which runs in the direction of the catch  13 . The slot of the arcuate strip  11  carries the reference sign  30 . Also, as far as the tail  23  is concerned, a slot which follows in the corresponding direction is realized in order to secure the position of the arm  25 . 
     The clamping jaws  28  are associated with the clamping sections  7 ,  9  in a pivotably-movable manner. The corresponding geometrical axes extend parallel in space to the scissors-articulation pin  2 . It can be gathered that the ends of the clamping sections  7 ,  9  provide bearing eyelets  31 . Bearing pins  32  are snapped into said bearing eyelets. Corresponding locating slots are positioned in front of the eyelets. Bearing pins  32  of the clamping jaws  28  can easily be secured via said locating slots. The bearing pockets are formed such that access remains for the application of a release tool, so that the clamping jaws  28  can be exchanged. 
     The clamping pliers  1  function as follows: taking as departure point the stop-limited basic expanded position of the pliers arms  4 ,  5  which is illustrated in FIG. 2, it is possible for the mouth  10  of said pliers arms to be reduced with gripping of an object. This takes place by the handle sections  6  and  8  being pressed toward one another, in the direction of the handle inner sides, counter to the action of the expanding spring  26 . The flat sides of the clamping jaws  28 , said flat sides being directed toward one another, can move, pivoting about the bearing pins  32 , into abutment flush against a, for example, plate-like object. The clamping pressure is then exerted. The clamping pliers  1  then hold themselves firmly against the object. The clamping force is maintained by an elastic deformation of the clamping sections  7 ,  9 . 
     As can be gathered from FIG. 7, it is also possible for the clamping surfaces of the clamping jaws  28  to be profiled. There is illustrated a symmetrical square cross-sectional profile  33  in the form of partial V-channels which are located transversely to the pivoting plane of the pliers arms  4 ,  5 . In order, nevertheless, to ensure the necessary resilience of the pliers arms  4 ,  5 , the U-profile cross-section of the same is additionally reinforced by a longitudinal web  34  extending from the U-base. 
     If it is intended to release the clamping action, all that is required is for the handle section designated by  6  to be gripped, i.e. to be positioned in the hollow of the hand and merely for the catch  13  to be pressed using one finger of said hand. The catch is thus unlatched. The clamping pliers  1  move back, by spring action, into their basic expanded position according to FIG.  2 . In this case, the clamping force of the pliers is greater than the force which is necessary for release of the catch  13 . 
     The expanding spring  26  serves both as a restoring spring for the clamping pliers  1  and also for subjecting the catch  13  to loading in the engagement direction. 
     If the clamping pliers  1  are to be moved into a space-saving storage and/or packaging position, all that is required is for the handle sections  8 ,  9  to be moved toward one another. In this case, the catch  13  moves with ratchet action over the toothing formation  12  of the arcuate toothed strip  11 . A self-securing closure position is then present, it being possible for said position to be released again in the manner described above by pressure on the actuating button  17 . 
     The actuating section  17  or the catch  13  forming it is suitably made to stand out by being of a contrasting color. 
     The clamping or expanding pliers according to the second exemplary embodiment (FIG. 9 ff.) is basically of the same construction apart from a specific configuration of the functional parts formed by the catch/actuating section  13 / 17 . The reference numerals are used analogously, in some cases without repetitions in the text. 
     Thus, in this case, catch  13  and the actuating section  17  are no longer in one piece, but are formed in two parts, these being associated in an articulated and displaceable manner. 
     The actuating section  17 , which functions as a pivoting pushbutton, is fitted onto the pin which provides the rotatable mounting of the actuating section, designated below as bearing pin  19  in the pliers arm  5 . It is also the case that a catch tail  35 , which projects from the catch  13 , is secured by the bearing pin  19 . For this purpose, said catch tail  35  has a through-passage in the form of a longitudinal slot  36 . The latter allows a limited displacement of the catch  13  relative to the pin. The longitudinal slot  36  extends directionally essentially tangentially, but spaced apart from the arcuate toothed strip  11  of the pliers arm  4 . 
     A second means for securing the catch tail  35 , said second means being closer to the catch  13 , is provided in the form of an angled slot  37 . This slot  37  is located between the longitudinal slot  36  and a neck  38  of the catch  13 . The plate-like catch tail  35  has the necessary width for this purpose. 
     It can be seen that in regard to the angled slot  37 , there is in question a heart-shaped through-passage. This is right-angled and has a first slot section  37 ′. The latter is roughly aligned with the scissors-articulation pin  2  and, in the clamping position of the clamping pliers  1 , runs transversely to a connecting line x—x between tooth-engagement point  39  of the catch  13  and the bearing pin  19 . Its catch-head-side flank F is similar to an undercut. It is located at just under 90° to the line x—x. 
     The second slot section  37 ″ extends, in the said position, in a direction which runs substantially parallel to said connecting line x—x. 
     A disengagement pin  40  serves as securing means in the direction of the actuating section  17 . With actuation of the blocking device, said disengagement pin changes over from the first slot section  37 ′ of the angled slot  37  into the second slot section  37 ″ of the same. 
     The second slot section  37 ″ extends in the same direction as the longitudinal slot  36 . The two are of the same length. The axial length of the disengagement pin  40  corresponds substantially to the thickness of the likewise plate-like actuating section  17 . The actuating section  17  has in each case a bearing eyelet  41  for entry of the ends of the disengagement pin  40 . In the receiving region of the catch tail  35 , the actuating section  17  is provided with a receiving recess  42  which is dimensioned in accordance with the movement requirement of the catch tail  35 , which is guided therein. The blockingly acting head of the catch  13  is located outside the boundary of the actuating section  17  and/or the guide pocket formed by the same, and can be perceived to be widened at the end. 
     As can be gathered from the drawings, it is not only the actuating section  17  here, but at the same time also the encased body of the catch tail  35 , which is forced in the direction of a basic position by the arm  25  of the expanding spring  26 . 
     The flattened ends of the disengagement pin  40  are guided on the insides of the window  20  of the pliers arm  5 , through which the pliers arm  4  engages. The bearing eyelet for the bearing pin  19  is designated by  43 . A bore  44  in the handle section  8  of the pliers arm  5 , through which the pliers arm  4  engages, is located opposite this bearing eyelet  43  of the actuating section  17 , in a congruently aligned manner. 
     Longitudinal slot  34  and angled slot  37  make it possible, upon the first actuation in the clamping position, for catch  13  and actuating section  17  to be pivoted toward one another and to be displaced. Pivoting takes place immediately. This actuation results in the spacing between the tooth-engagement point  39  of the catch  13  and toothing formation  12  and the bearing pin  19  being shortened by a first actuation of the actuating section  17  such that the two clamping sections  7 ,  9  are disengaged from the clamping position (see FIGS. 12 and 15) into a release position (see FIGS.  13  and  17 ). In this case, as can be gathered from FIG. 17, the tooth engagement between the toothing formation  12  of the arcuate toothed strip  11  and the mating toothing formation  14  of the catch  13  is maintained. The disengagement operation taking place in this manner shortens, via the free movement provided by the second slot section  37 ″, the supporting length between tooth-engagement point  39  and said bearing pin  19 . A limited opening movement takes place in the region of the knuckle joint G and raises the clamping jaws  28  away from a gripped object  45  (see FIG.  13 ). Accordingly, this is all achieved by the guide-slot-like control of the ratchet unit, that is to say via the disengagement pin  40 , which is associated with the actuating section  17  and engages in the angled slot  37  of the catch  13 . Said disengagement pin, in the position associated with the clamping position, is in blocking engagement in the first slot section  37 ′, which runs substantially transversely to the connecting line x—x between tooth-engagement point  39  and bearing pin  19 , supported by the flank F, and, in the position associated with the release position, is in the second slot section  37 ″, which runs substantially parallel to the connecting line x—x. This proceeds via the intermediate position which is illustrated in FIG. 16, in which the flank support of the slot section  37 ′ comes to an end. The disengagement pin  40  moves via the vertex zone into the other, that is to say second slot section  37 ″, and/or the catch tail  35  overruns the same. This displacement takes place without pivoting in relation to the actuating section  17  as a result of the slot section  37 ″ and longitudinal slot  36  running in the same direction. It is even possible for the longitudinal axes of the slots to be aligned coaxially. In this securing position, the now functionally single-part catch  13 / 17  can be used for further actuation, i.e. the second actuation of the actuating section  17  is initiated, the blockingly acting tooth engagement  12 / 14  being released. The tool can enter into the maximum expanded position according to FIG. 18, forming a large pliers mouth  10  for gripping the object  45 . 
     As can be gathered from FIG. 17, the tooth engagement is restricted there to the upwardly-located end tooth and, if appropriate, partial engagement of the next-following tooth. It is easily possible for this position to be disengaged; this is because, with close-fitting blocking engagement of the teeth, multiple interengagement is provided as a result of the sawtooth-like structure. The blockingly active flanks of the teeth and tooth gaps thus always provide initially a short, relatively firm clamping action prior to the unblocking operation. It can be gathered from FIG. 17 that the lower end tooth of the mating. toothing formation  14  of the catch and most of the next-following teeth are already disengaged from the toothing formation  12 . 
     All disclosed features of this application are pertinent to the invention. The disclosure content of the associated/attached priority documents (copy of the prior application) is hereby also included as to its full content in the disclosure of the application, also for the purpose of incorporating features of these documents in claims of the present application.