EP0103912B1 - Pliers device - Google Patents

Description

The invention relates to a pliers device with a device body and of the type specified in the preamble of the appended claim 1, that is to say a pliers device in which the one working jaw instead of the scissor-like pivoting movement, which is usually the case with pliers, performs a vise-like linear movement with respect to the other working jaw. A known device of this type is e.g. in which Pressmaster A.G. British Patent Application No. 1,453,479 shown in Fig. 2.

The linear guideway of the movable jaw is subjected to rather great efforts in devices of this type, because the drive arm member (this term in the present description means the last link of the toggle mechanism acting directly on the relevant jaw) acts at least temporarily on the movable jaw at an angle to the guideway, and possibly with considerable strength. The guideway must be designed with special regard to the absorption of the component of the force acting perpendicular to the guideway, and nevertheless wear effects cannot be completely ruled out which impair the accuracy of the guideway because they cause an undesired play in the direction of the named component due to wear.

Another device of this type is described in German Patent No. 273,847 by E. F. Prieto. This is a sealing pliers which has a housing to which an operating handle is rigidly connected and a second operating handle is connected in an articulated manner.

A sliding body or jaw support is slidably arranged in the housing in a straight guide track. The guideway has guide members below and above the jaw carrier, but the guide member above the jaw carrier is interrupted in the working area of a work jaw carried by the jaw carrier and the guideway is thus open at this point to the next occupying end edge of the housing.

The articulated handle has two rigid extensions beyond its articulation point, each of which forms an eye for receiving a handlebar. The jaw carrier is driven by an elongated drive arm member or lever which is pivotally mounted in the middle of the housing at a location which is located below the lower guide member of the guideway. The drive arm member is connected at one end to one of the mentioned links, and engages with its second end, which is provided with a pressure roller, into a recess in the body of the jaw carrier, where the pressure roller at two opposite points on its circumference with two walls of the recess intervenes.

With this construction, the above-mentioned stress on the guideway is eliminated by an oblique component of the driving force.

It can be seen from the above that the drive arm element works as a two-armed lever with the base in the central articulation point. If such pliers should be used for work tasks that require significantly greater force such as the pressing of soft lead seals, one arm of the two-armed lever would have to be extended significantly, which inevitably leads to an increase in the total length of the drive arm member and, if necessary, also of the housing .

In many cases, it is desirable for pliers that a work jaw acts on a work object with greater force in the final phase of a machining operation, such as pressing or the like, than at the beginning when less resistance is felt.

The effect of force is understood to mean the ratio 3M, where W is the change in the mutual position of the operating handles of the device, and V is the corresponding rectilinear approach movement of the work jaws. In the initial phase of processing, a higher value of WV is desired in order not to make the total working time unnecessarily long, whereas in the final phase a lower 11 value is desired in order to achieve greater force per unit of W.

The invention has for its object to provide a pliers device of the type mentioned in which the stress on the guideway transverse to its direction is eliminated or at least considerably reduced, which with unchanged extent increases leverage on the drive arm member and at the same time, thanks to the limited design, increased resistance of the guideway and which, if necessary, in a further development may have a declining value in the course of the work operation.

The object of the invention is achieved by means of the characteristics cited in the characterizing part of claim 1, advantageous further developments being set out in the attached subclaims.

• in Fig. 1 eine erste Ausführungsform des erfindungsgemässen Gerätes,
• " Fig. 2 eine zweite Ausführungsform,
• " Fig. 3 eine Abwandlung des Gerätes gemäss Fig. 2,
• " Fig. 4 eine dritte Ausführungsform,
• " Fig. 5 das Gerät gemäss Fig. 4 in geschlossener Lage,
• " Fig. 6 ein Detail desGerätes gemäss Fig. 4 und 5 in grösserem Masstab und in Schnitt entlang der Ebene VI-VI in Fig. 4,
• " Fig. 7 ein kinematisches Schema der Arbeitsweise des Gerätes gemäss Fig. 4 und 5, und
• " Fig. 8 eine Abwandlung des Gerätes gemäss Fig. 4 och 5.

The invention will now be explained in more detail with reference to the attached schematic drawings, the side views of which are shown in the individual drawing figures:

• 1 shows a first embodiment of the device according to the invention,
• 2 shows a second embodiment,
• 3 shows a modification of the device according to FIG. 2,
• 4 shows a third embodiment,
• 5 shows the device according to FIG. 4 in the closed position,
• "FIG. 6 shows a detail of the device according to FIGS. 4 and 5 on a larger scale and in section along the plane VI-VI in FIG. 4,
• 7 is a kinematic diagram of the operation of the device according to FIGS. 4 and 5, and
• 8 shows a modification of the device according to FIGS. 4 and 5.

Parts with an identical or analog function are identified with identical or analog reference symbols in all drawing figures.

1, a pliers device according to the invention has a device body 10 which is rigidly connected to a structural unit 100 with a first operating handle 11. A second operating handle 12, which has a rigid extension 12a beyond its articulation point, is articulated to this assembly 100 by means of a pivot pin member 15a. Arranged in the device body 10 is a rectilinear guideway 13 ′, 13 ″ for a jaw support 20 which is displaceably arranged therein and can be driven by the second operating handle 12 and which carries an exchangeable first working jaw member 21 by means of a retaining screw 21a.

The direction E of the fixed handle 11 runs essentially parallel to the direction F of the guideway. A cooperating second work jaw member 22 is fixedly arranged in the device body 10 at the end of the guideway 13 ', 13 "by means of a retaining screw 22a. It is obvious that both work jaw members 21, 22 are also incorporated as non-exchangeable elements directly in the jaw support 20 or device body 10 , can.

So far the arrangement is conventional (with the exception of the design of the guideway 13). According to the invention, there is not a drive arm member in the above-mentioned sense, i.e. as the last link which acts directly on the jaw carrier, but such a drive member 14 is articulated in a fixed manner to the device body 10 by means of a pivot pin 14a, specifically at a point which is at a distance K from the guideway 13 ', 13 ". The distance K runs transversely to the direction F of the guideway 13 ′, 13 ″ and on the opposite side thereof from where force is applied to the drive arm member 14, which is connected in an articulated manner to the drive arm member at 14b and to the extension 12a at 15b by means of a pivot pin member Link tab organ 15 happens.

The drive arm member 14 also extends transversely to the direction F of the guideway, and the connecting line A of the two articulation points 14a, 14b occupied on the drive arm member includes an angle a with the direction F, which, when the device is open, is between 45 ° and 135 ° and approximately in the example shown Is 90 °. In the present description, an open or closed state is understood to mean the state with working jaw organs that are distant or approximated to one another.

In its central area, approximately halfway between the two articulation points 14a, 14b, the drive arm member 14 carries a pin 14c which engages with the rear end wall 20a of the jaw support 20 and can slide along the wall 20a in the direction of the line A. A compression or pull spring element, not shown, can ensure permanent engagement of these two parts, i.e. also outside of the actual work process.

It is known to use pliers of this type, including handles, made of two parts, such as 100a, 100b (Fig. 6), e.g. metal plates connected by spacers, between which there is a central free space 100 '. The devices according to the invention can also advantageously be produced in this way, and their drive arm and connecting link elements can then either consist of a single drive arm arranged in the said central free space or a single connecting link, or each of a pair of these elements such as drive arms 14; 14;, one of which is arranged along an outer surface of the device. 1 is provided with a pair of drive arms and a single connecting strap. In this construction, the guideway can advantageously be formed by windows 13 with long edges 13 ', 13 "arranged in both side parts, the cheek piece having a central part which extends somewhat more into the free space 100' and is therefore also guided laterally by the side parts .

The drive arm member anchored in the device body 10 only transmits forces acting in the direction F of the guideway to the jaw carrier. The fact that the guideway is designed in the form of a window 13 arranged in the device body, which is closed on all sides and does not, as usual, merely have a guide member 13 'under the cheek carrier 20, but also above the cheek carrier with a second, parallel guide member 13 ", further helps to prevent premature wear of the cooperating surfaces of the guideway and the jaw support. Such wear means that the end position of the work jaw organs is no longer clear, and this can be the case with work jaws with a shape other than straight lead to faultless machining of workpieces.

In the embodiment according to FIG. 2, the direction E of the first operating handle 11 extends obliquely to the direction F of the guideway, and forms an angle g of approximately 45 ° with the latter. The second operating handle 12 is articulated by means of the pivot pin 15a to a fixed projection 10a of the device body 10 and has one in its extension 12a elongated slot 12c in which the pin 14b of the drive arm member 14 is slidably guided. The point of engagement of the pin 14b with the slot 12c moves in this slot when the handle 12 is actuated, but remains here, like the device according to FIG. 1, at an unchanged distance from the pivot pin 14a, ie it moves along a circular path H. the center in the pivot pin 14a.

The embodiment according to FIG. 3 is a kinematic revolution of the embodiment according to FIG. 2 in the sense that an elongated slot 14d in the drive arm member 14 and an engagement pin 12b is arranged on the extension 12a. In this case too, the point of engagement of the pin 12a moves along the slot 14d when the handle 12 is actuated and moves along a circular path with a fixed center, but this is now in the pin 15a. A kinematic difference between the embodiments according to FIGS. 2 and 3 and the other exemplary embodiments shown, which will be discussed in more detail later, is that when the handle 12 is actuated, the distance M 'between the pins 12a and 15a in the device 2, as well as the distance P between the pin 14a and the point of engagement in the slot 14d in the device according to FIG. 3, is approximately extended.

In the third embodiment according to FIGS. 4 and 5, a second operating handle 12 in the embodiment as shown in FIG. 3 is not articulated directly to the structural unit 100, but by means of a connecting link member 15 ', similar to the connecting link member 15 according to FIG. 1.

The first operating handle 11 extends obliquely to the device body 10 and preferably so; that the direction of the guideway 13 with the direction E of the first operating handle includes an angle li in the order of magnitude of 30 ° to 90 °, and with the axis of symmetry D of the most open operating handles 11, 12 an angle g of 45 ° to 90 ° . The line of symmetry D is understood to mean that line which halves the angle 8 enclosed by the two operating handles 11, 12 in their mostly open position.

The drive arm member 14 engages in the area between its two articulation points 14a, 14b with the jaw support 20 such that a mutual sliding movement in the longitudinal direction of the drive arm is possible between the two parts. In the example shown, this is achieved in that the pin 14c firmly anchored therein approximately half the length of the drive arm 14 'passes through an elongated hole 20b arranged in the jaw carrier 20. On the opposite side of the device body 10 there is an identical or further drive arm 14 "(Fig. 1,2) in which the opposite end of the pin 14c is anchored. However, it is obvious that other solutions for the sliding engagement of these two parts are possible, For example, a pin which is firmly anchored in the jaw support 20 and which slides into the drive arm member in elongated holes, or the solution according to FIG. 1.

In the jaw carrier 20 and in the device body 10, at the end of the guideway 13 ', 13 ", the cooperating working jaw members 21, 22 are arranged as before. In the example shown, it is a pair of jaws for pressing cable lugs onto electrical conductors, but it is obvious that any work jaw organs can be used.

The device is expediently provided with a locking mechanism which is known per se and prevents the operating handles and the work basin organs from opening prematurely. In the example shown, a locking mechanism is shown which comprises a circular row of teeth 15c and a locking hook 15c 'engaging with it. Such a locking mechanism for pliers is described in the Holdema A.G. British Patent 1,522,144, filed October 25, 1974, which is hereby incorporated by reference. Alternatively, a locking mechanism acting between the two operating handles can be used, e.g. is described in the former British Patent 1,453,479.

Furthermore, for precise adjustment of the closed end position of the device shown in FIG. 5, at least one of the pins 14a, 14b, 14c, 15a, 15b can be carried out eccentrically in known embodiments according to FIG. 6, as shown in FIG. 4 and 5 is shown for example in the pin 15a. The same applies to the pins 12a, 12b in the embodiment according to FIG. 3.

The peg in question, that is to say 15a in the example shown, has two peripheral parts 15a ', 15a which are concentric with a longitudinal axis C, and an intermediate part 15a' 'between which is eccentric to this axis C and on which the connecting lug 15 '. By means of the concentric parts 15a', 15a ", the pin 15a is mounted in the two side parts 100a and 100b of the assembly 100, so that its rotation around the axis C causes the opposite position of the two of such a pin connected components can be changed as part of the eccentricity. To carry out and secure such an adjustment, the pin 15a is provided with a slotted head 150 and with a thread on which a tightenable nut is screwed. For further details regarding such a setting arrangement, reference is made to the British patent specification 1,522,144.

The device according to the invention is advantageously designed in such a way that, in the completely closed state according to FIG. not in the open state, as shown in Fig. 1, the drive arm 14 or the connecting line A of its two articulation points 14a, 14b essentially a right angle a or at least an angle which is in the range 80 ° to 100 °, with the guide track 13 includes. The same also applies to the angle β_ with respect to the connecting line B of the two articulation points 14b, 15b located on the extension 12 '. With these angle values, the best power yield is achieved in the final phase of the jaw approach.

The device works in the following way, as can best be seen in FIG. 7: After inserting a work object (not shown) between the two work jaw members 21 22 in the open state of the pair of jaws, the device is actuated by the second operating handle 12 in the direction of the arrow P on the first operating handle 11 is approximated. The second operating handle 12 here performs a rotary movement around the pin 15b, its rigid extension 12a moving in the direction of the arrow P _{2 in the} opposite direction of the arrow P ₁ . As a result, the drive arm member 14 is rotated in the direction of the arrow ₃ P around its articulation point 14 a on the device body 10 and thereby gives the jaw support 20 a feed movement in the direction of the arrow P ₅ , which, thanks to the guide track 13, is straight. As a result of the rotational movement around the pin 14a, the two other pins 14c and 14b located on the drive arm member 14 describe circular movements along the paths G and H with centers in the pin 14a. In order to make this possible, on the one hand the engagement of the drive arm member 14 with the jaw support 20 is designed in a sliding manner in the manner mentioned above, and on the other hand the second operating handle 12 is not articulated directly on the assembly 100 but on the connecting bracket 15 ', which compensates for the vertical Component of said circular movement itself performs a circular movement in the direction of arrow P ₄ and thus enables the second operating handle 12 to be “lifted” (see FIG. 4 with FIG. 5).

• a) Der Antriebsarm 14 greift innerhalb des mittleren Drittels des Abstandes 1 zwischen 14a und 14b mit dem Backenträger 20 ein, vorzugsweise in der Mitte (t/2). b) Die Abstände M zwischen 14b und 15b einerseits und n zwischen 15a und 15a anderseits sind im wesentlichen einander gleich und unterscheiden sich höchsten um + 25%.
• c) Der oben genannte Abstend bildet ein Dreibis Vierfaches der Abstände m oder n

It has been found that the following aspect ratios are advantageous:

• a) The drive arm 14 engages within the middle third of the distance 1 between 14a and 14b with the jaw carrier 20, preferably in the middle (t / 2). b) The distances M between 14b and 15b on the one hand and n between 15a and 15a on the other hand are essentially the same and differ by a maximum of + 25%.
• c) The above-mentioned trend is three to four times the distances m or n

FIG. 8 shows a deflection of the device according to FIGS. 4 and 5, which differs only in that the direction E of the first operating handle 11 is essentially parallel to the direction F of the guide track, as in the embodiment according to FIG. 1.

The embodiments acc. 2 and 3 differ from all the other embodiments shown, for example, in that the lever arm with variable length m 'acting between the articulation or engagement points 15e and 14b in the embodiment according to FIG. 2 or p between the articulation point 14e and The engagement point in the slot 14d in the embodiment according to FIG. 3 grows somewhat when the operating handle 12 is actuated, which in turn results in a somewhat less pronounced reduction in the value Im, but the difference is insignificant.

In all embodiments of the device according to the invention, loads acting on the latter and / or the jaw support 20 transversely to the direction F of the guideway are applied by the fixedly articulated drive arm morning, and forces acting only in the aforementioned direction F are transferred to the jaw support. The design of the guiding device in the form of a window 13 closed on all sides, and in particular both below and above you, above the cheek piece, further contributes to precise guiding with minimal wear.

Claims (9)

1. A pliers-type tool comprising a tool body (10) which is with a first opareting handle (11) combined to a rigid sub-assembly unit (100) in which a rectilinear guiding track (13) is provided for slidable displacement of a jaw carrier (20) for a first working jaw (21) which co-operates with a second working jaw (22) stationarily mounted on the tool body at an end of the guiding track, a second operating handle (12) being pivotally connected to said sub-assembly unit (100), a rigid extension (12a) extending beyond the point (15a) of pivotal connection, a first end of an elongated driver arm means (14) for driving said jaw carrier (20) and extending transversely of the direction (F) of said guiding track being actuable by said extension, said driver arm means being at a pivot point (14a) which is spaced (C) from the first end of said means (14) end transversely spaced from seid guiding track (13) pivotelly connected to the sub-assembly unit, cherecterised by the last mentioned pivot point (14) being loceted on the driver arm means (14) on the second end thereof, end in the tool body (100) on the opposite side of the guiding treck than where the first end of the driver arm means (14) is located, and by the driver arm means (14) being in engagement with the jaw carrier (13) at its central part between the two ends and thus being arranged to operate as an one-armed lever, the guiding track being provided with uninterrupted guiding members (13',13") as well above, as beneath the jaw carrier, and defined by a window limited on all sides.

2. A pliers-type tool according to claim 1, characterised by said extension being in slidable engagement with the driver arm means (Figs. 2,3).

3. A pliers-tool according to claim 1, characterised by the second operating handle being in a known manner connected to said sub-assembly unit with the aid of a connecting link means (15) pivotally attached at both its ends, and with the aid of a pivot pin (14b) being stationarily connected to said driver arm means, whereby said connecting link means is adapted to execute, upon a pivotal movement of the second operating handle, by a pivotal movement of its own a displacement of the last mentioned pivot pin along a circular path (H) centered about the point of pivotal connection of said driver arm means to the sub-assembly unit.

4. A pliers-type tool according to claim 3, cheracterised by the distance (n) between the two pivot points (15a,15b) of the connecting link means, and the distance (m) between the two pivot points (14b,15b) located on said extension (12a) of said second operating handle being within a maximum range of ± 25% of one another.

5. A pliers-type tool according to one of the preceeding claims, characterised by as well the direction (E) of the first operating handle, as the axis of symmetry (D) of the two operating handles extending obliquely (r,r') to the direction (F) of the guiding track.

6. A pliers-type tool according to claim 5, characterised by the direction (F) of the guiding track forming with the axis of symmetry (D) of the completely open operating handles an angle (₄) in the range of 45° to 90°, and with the direction (E) of the first operating handle an angle (µ ) in the range of 30° to 90°

7. A pliers-type tool according to any of the preceeding claims, characterised by a connecting line (A) extending between the pivot point (14a) of the driver arm means relative to the tool body and the point of engagement (14b,14d) of the extension (12a) of the second operating handle forming, at least when said jaw carrier is in the end position,an angle (α) in the range of 80° to 100° with the direction (F) of the guiding track.

8. A pliers-type tool according to any one of the preceeding claims, characterised by either the connecting link means, or the operating handles, being in known manner provided with an arresting mechanism (15c,15c') for impeding premature opening.

9. A pliers-type tool according to any one of the preceeding claims, characterised by at least one of the pins (12b,14a,,14c,15a,15b) by which the sub-assembly unit (100), the driver arm means (14), the jaw carrier (20) and the connecting link means (15,15') are pivoted one to another being for adjustment purposes in known manner provided with a concentric portion and an excentric portion (15a',15a",15"').

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