WO1995023048A1

WO1995023048A1 - A tool arrangement

Info

Publication number: WO1995023048A1
Application number: PCT/SE1995/000102
Authority: WO
Inventors: Mats Norin
Original assignee: Pressmaster Tool Ab
Priority date: 1994-02-25
Filing date: 1995-02-02
Publication date: 1995-08-31
Also published as: SE9400658L; SE9400658D0; SE501205C2

Abstract

A tool includes first and second jaws (1, 2) which can be moved relative to one another between an open and a closed position, and two handles (6, 7), which can be pivoted relative to one another for movement of the jaws and each of which extends rearwardly from its respective jaw, wherein at least one handle (6) is pivotally connected at its forward end to an associated jaw (1) at a first pivot point (8), and wherein a pressure force transmission link (9) extends obliquely rearwards from a second pivot point (10) on said one handle (6) behind the first pivot point (8) to a third pivot point (11) on the second handle (7). The link (9) includes at least one part (17, 18) which curves outwardly in relation to an imaginary straight line (16) joining the second and the third pivot points (10, 11) and which forms a bending zone, wherein the link (9) is intended to bend or flex in a plane that extends perpendicular to the pivot axes of the link in correspondence with the pressure forces acting on the link.

Description

A TOOL ARRANGEMENT

The present invention relates to a tool of the kind which includes first and second jaws that can be moved relative to one another between an open and a closed position, and two handles which can be pivoted relative to one another so as to move the jaws and each of which extends rearwardly from its respective jaw, wherein at least one handle is pivotally connected at its forward end to an associated jaw at a first pivot point, and wherein a pressure force transmission link extends obliquely rearwards from a second pivot point on said one handle behind the first pivot point to a third pivot point on the second handle.

Particular arrangements for obtaining increased resilience or springiness in tools of this kind are earlier known from GB Patent Specifications 1,581,725 and 2,072,081, for instance. These known arrangements, however, complicate the tools and make them more expensive.

The object of the present invention is to provide a novel and advantageous arrangement for increasing the springiness of a tool without complicating the tool or making it expensive.

To this end, it is proposed that the link of a tool of the kind defined in the introduction will have at least one part which curves outwardly in relation to an imaginary straight line connecting the second and the third pivot points and which forms a bending zone, wherein the link is constructed to bend or flex in a plane that extends perpendicular to the pivot axles of said link correspondingly to pressure forces acting thereon. This arrangement enables the simplicity of the tool to be retained while essentially improving the springi¬ ness of the tool.

Further features characteristic of the invention and advantag¬ es afforded thereby will be apparent from the depending Claims and from the following description of a non-limiting exempli¬ fying embodiment of the invention shown schematically in side view in the accompanying drawing.

The drawing illustrates a press tool intended for pressing operations, with the tool shown in a closed position. The tool includes two jaws 1, 2 which are provided with suitable exchangeable inserts 3, 4 which are constructed for pressing end-contacts of three different dimensions onto electric conductors. The jaws 1, 2 can be pivoted relative to one another between the illustrated closed position and an open position by pivoting the jaw 1 around a pivot point 5. When the tool is in its open position, one end of a conductor and an end-contact which is to be fastened thereto can be inserted into an appropriate recess in the inserts 3, 4 with the jaws open. The jaws 1, 2 are pivoted relative to one another with the aid of handles 6, 7, each of which is connected to a respective jaw and extends rearwardly therefrom. The jaw 2 is rigidly connected to the handle 7, whereas the jaw 1 is pivotally connected to its handle 6 at a pivot point 8. A pressure force transmission link 9 extends obliquely rearwards from a further pivot point 10 on the handle 6 behind the pivot point 8, to a pivot point 11 on the handle 7. It will be seen that the handle 6, the link 9 and the pivot point 8, 10, 11 form a toggle lever which functions to swing the jaw 1 towards or against the jaw 2 about the pivot point 5 with a large force when the handles 6, 7 are swung together with a moderate force. Mounted between the handle 7 and the jaw 1 is a pull spring 12 which endeavours to swing the jaw 1 in an anti- clockwise direction, i.e. to the open tool position.

To prevent the interruption of a pressing operation before the jaws 1, 2 have been swung to their fully closed position and also to prevent interruption of tool movement, the link 9 has a toothed camming surface 13 which is curved arcuately with its centre of curvature located in the point 10. The camming surface 13 coacts with a cam follower 14 provided in a V-slot 15 formed in the handle 6, the legs of the V being directed obliquely away from the camming surface 13. A pull spring (not shown) which acts between the cam follower 13 and the pivot point 10 for instance acts on the cam follower 13 in a direction towards the bottom of the V-slot 15. An arrangement of this kind is earlier known from WO 93/19897, and conse¬ quently a more detailed description of the arrangement is thought to be unnecessary.

The link 9 includes parts 17, 18 which are curved outwardly in relation to a straight line 16 joining the pivot points 10, 11. These parts 17, 18 form bending zones in which the link 9 is bent or flexed further in the plane of the drawing in response to pressure forces applied thereon in the direction of the line 16 when the tool is in use, i.e. a plane which forms a right angle with the axes about which the handle 6,

7, the jaws 1, 2 and the link 9 are pivotal in the points 5,

8, 10 and 11. Such further bending or flexing will result in shortening of the link 9 in the direction of the line 16. When the parts 17, 18 are mutually asymmetrical, this bending or flexing of the link will cause the link 9 to pivot relative to the handles 6, 7 at the points 10 and 11. This can result in an undesirable effect on the arrangement 13-15, because the initial and final positions of the arrangement may be affected in a manner which is difficult to control. Consequently, the dimensions of the link 9, the configuration, size and posi¬ tioning of the outwardly curved parts in relation to the line

16 are adapted advantageously so that pivotal movement at the points 10, 11 deriving from bending the link 9 in the bending zones will be excluded at least to a large part. It is necessary in this regard for the link 9 to have at least two curve parts 17, 18 which are each bent outwardly in mutually different directions in relation to said line 16 and which, in addition, require little space. Flexing of the part 17 which curves outwardly in one direction as a result of pressure forces applied to the link 9 will preferably also correspond to the flexing of the part 18 which curves outward- ly in the other direction, such that the pivotal movements caused thereby will cancel out one another and such that the net result will solely be a shortening of the link 9 along the line 16.

It will be understood that the invention is not restricted to the illustrated and described exemplifying embodiments thereof and that the invention can be realized in any desired manner within the inventive concept defined in the Claims.

Claims

1. A tool which includes first and second jaws (1, 2) that can be moved relative to one another between an open and a closed position, and two handles (6, 7), which can be pivoted relative to one another for movement of the jaws and each of which extends rearwardly from its respective jaw, wherein at least one handle (6) is pivotally connected at its forward end to an associated jaw at a first pivot point (8), and wherein a pressure force transmission link (9) extends obliquely rearwards from a second pivot point (10) on said one handle (6) behind the first pivot point (8) to a third pivot point (11) on the second handle (7), characterized in that the link (9) includes at least one part (17, 18) which curves outwardly in relation to an imaginary straight line (16) joining the second and the third pivot points (10, 11) and which forms a bending zone, wherein the link (9) is intended to bend or flex in a plane that extends perpendicular to the pivot axes of the link in correspondence with the pressure forces acting on the link.

2. A tool according to Claim 1, characterized in that the link (9) includes at least two parts (17, 18), each of which curves outwardly in respective opposite directions in relation to said line.

3. A tool according to Claim 2, characterized in that the arrangement is such that bending or flexing of the part (17) which curves outwardly in one direction caused by the applica- tion of pressure forces on the link (9) so corresponds to the bending or flexing of the part (18) which curves outwardly in the other direction that bending of said parts will only result in shortening of the link (9) and will not cause the link to swing about its pivot points (10, 11).