DE102011000200B4 - Automatic locking pliers - Google Patents

Abstract

Automatic locking pliers with - a fixed pliers part (01) with a first pliers jaw (02) and a fixed handle (03); - One on the fixed pliers part (01) pivotable second jaw (04) with a swivelable handle (07); - A support lever (09) which is articulated between the handles (03, 07), mounted and which forms an elbow lever with an upper portion of the pivotable handle (07); and - a locking element (13) which in the direction of the longitudinal axis of the fixed pliers part (01) on a guide pin (14) by means of an axially continuous guide opening (20), which in a guide part (17) of the locking element (13) is provided displaceable mounted and hinged to the support lever (09) is connected, wherein the locking element (13) by tilting over a tilting point (23) relative to the guide pin (14) can be locked; characterized in that a lateral surface (18) of the guide opening (20) of the guide member (17) on an opposite longitudinal side of the guide pin (14) to the support lever (09) in an axial end portion (19) of the guide member (17) through an opening (25 ) is opened, of which the guide pin (14) during tilting of the locking element (13) is receivable; wherein a guide surface (21) at least over the length of the end portion (19) on the longitudinal side opposite the opening (25) is formed to ensure a guide of the untilted locking element (13) on the guide pin (14); and wherein a guide portion (22) of the guide opening (20) with its lateral surface (18) surrounds the guide pin (14) in order to limit the tilting of the locking element (13).

Description

The invention relates to an automatic locking pliers according to the preamble of claim 1.

Grip pliers have been available for many years in a variety of sizes and versions. Its special feature is the toggle mechanism. By extending the toggle lever and the subsequent holding close to the extended toggle lever position, high clamping forces can be achieved.

Generic grip pliers comprise a fixed pliers part with a first pliers jaws and a fixed handle and a movable pliers part with a second pliers jaws and a pivotable handle. Between the handles, a support lever is arranged, which forms the knee lever with an upper portion of the pivotable handle. For automatic adjustment of the mouth width of a workpiece to be held, a locking element on a Fuhrungsachse, which preferably extends along the longitudinal axis of the fixed handle, slidably mounted. The locking element can be clamped by tilting on the guide axis.

The purpose of grip pliers is very versatile and is often influenced by the design of the jaws. Usually they are used for short clamping, holding or fixing of various workpieces, in order to ensure subsequent processing in the desired position or position.

In order to set the desired clamping force and the required mouth opening, conventional grip pliers have an adjusting screw on the housing, which together with the housing forms the counter bearing of the toggle lever. Turning the screw, the position of the toggle lever bearing changes and thus also the clamping force and the opening width of the forceps jaw.

From the US 7 721 630 B2 is an automatically adjusting Gripzange known in which the locking is done via a sliding rod which is clamped by means of balls in a tapered opening. Various spring-loaded levers of the adjustment and release mechanism is realized.

From the US Pat. No. 3,208,319 A a grip pliers is known in which the locking element is tilted by a cam, which is connected to the support lever and the locking element, and thereby clamped on the guide shaft. Locking element and guide shaft have a grooved surface portion on the side facing away from the cam longitudinal side of the Fuhrungsachse or the opening to initiate the clamping safely. The preparation of the axially split two different surfaces is complex and it is a relatively large clearance between the guide shaft and locking element required.

The US Pat. No. 6,591,719 B1 and US Pat. No. 6,776,072 B2 show a grip pliers, in which the tilting of the locking element also takes place via a cam. About an adjusting screw, the angular position between the cam and the guide axis and thus the clamping force of the pliers can be adjusted. The adjusting screw is provided either on the cam or on the support lever.

The object of the invention is to provide a grip pliers with an automatic adjusting and locking mechanism, which can be produced from a few simple-shaped parts. The grip pliers should thereby be simple and inexpensive to produce despite high functionality.

The object is achieved by an automatic grip pliers having the features of claim 1.

The automatic grip pliers initially comprises in a known manner a fixed and a movable pliers part, each with a handle and a support lever arranged between the handles.

In the fixed pliers part, a locking element is displaceable against a spring force and tiltably mounted on a guide pin and hingedly connected to one side of the Stutzhebels. The axis about which the locking element is tiltable, is preferably parallel to the pivot axis of the movable pliers part.

The locking element has a guide part with an axially extending guide opening, preferably in the form of a guide bore. The guide bore is adapted to the cross section of the guide pin, so that the locking element is displaceable on the guide pin with a slight play. The lateral surface of the guide opening of the guide part is opened on an axial end section through an opening from which the guide pin can be received when tilting the locking element, so that the tilting of the locking element is made possible by a tilting point through the opening of the end section. Opposite the opening, a guide surface is formed at least over the length of the end portion in the lateral surface of the guide opening of the guide member to ensure a guiding of the untilted locking member on the guide pin. The tipping point is at the end of the Guide surface diagonally opposite the opening.

A guide portion of the guide opening surrounds with its lateral surface the guide pin, on the one hand to ensure a guiding of the untilted locking element on the guide pin and on the other hand to limit the tilting of the locking element, d. H. the existing in the Führungsoffnung game allows the tilting of the locking element up to a stop point at which it comes to locking the locking element relative to the guide pin. The lateral surface is preferably circumferentially closed in the end section, so that the guide opening completely surrounds the guide pin in the end section. The guide surface preferably extends into the guide section.

Tilting of the locking element takes place when the force component in the displacement direction at the point of attachment of the support lever is greater than the perpendicular thereto force component which urges the locking element with the guide surface against the guide pin, or if an extension line of the force introduced by the support lever force the guide surface no longer cuts.

The guide part is preferably formed as part of the locking element, which is integrally formed with the rest of the locking element.

The axis of the guide pin preferably coincides with the longitudinal axis of the fixed pliers part. The axis of the guide opening preferably coincides with the axis of the guide pin in the untilted state of the locking element.

The end portion and the Fuhrungsabschnitt the Fuhrungsoffnung close along the axial extent of the guide opening preferably directly to each other, wherein the axis of the guide opening in the end portion and the guide portion is formed. The guide part of the locking element is preferably oriented in such a way that the end section of the guide opening is arranged between the guide section and the first forceps jaw.

In a preferred embodiment of the invention, the guide pin and the guide opening each have a circular cross-section, wherein the diameter of the Fuhrungsoffnung preferably 1.01 to 1.40; more preferably 1.1 to 1.2 times the diameter of the Fuhrungsbolzens. This has the advantage that both the bolt, as well as the Führungsoffnung is easy to produce. The guide member then has in the guide section the circular Führungsoffnung, which completely surrounds the guide pin. In this embodiment, the end section preferably has an at least semi-cylindrical guide surface for guiding the locking element in the non-tilted state. The non-existent circumferential part of the at least semi-cylindrical guide surface represents the opening of the end section.

The angle through which the locking element tilts is determined by the diameter of the guide opening, the diameter of the guide pin and the height, d. H. the axial length of the guide section. This angle also determines the maximum clamping force.

Of course, other cross sections are possible, which allow, for example, an increased bending stiffness of Fuhrungsbolzens.

There are also different cross sections of guide pin and Fuhrungsöffnung conceivable as long as the guide surface and the Fuhrungsabschnitt allow both leadership, as well as clamping, for example elliptical or oval. The skilled person can determine such combinations. For example, the guide pin could have a circular cross-section flattened on both sides and the guide opening has a circular cross-section, while the clamping and guiding takes place in each case at the circular sections.

In the region of the guide opening, which is closed in cross-section, in particular at the axial ends of the guide section, one or more steps with an enlarged cross-section of the guide opening are advantageously provided, which reduces the tensile stress on the lateral surface of the guide section during tilting and thereby prevents "tearing" of the lateral surface.

Furthermore, a chamfer can be provided in the region of the steps in order to increase the surface pressure and to achieve a better clamping force. Optionally, the formation of the chamfer can be done by cold deformation.

The dimensions of the locking element, the guide surface, the opening must be coordinated so that the locking element slides along the guide pin and tilts safely falls below a certain force application angle of the support lever and initiates the clamping.

The line of movement of the locking element is predetermined by the Fuhrungsbolzen. By applying force outside of the predetermined by the guide surface movement line a tilting moment acts on the locking element. By providing the guide surface on the locking element, tilting of the locking element occurs only at a certain force introduction angle. As long as the force line of the force of the support lever cuts the guide surface, the locking element does not tilt.

To calculate the clamping force or the required dimensions of the locking element, the coefficients of friction of the materials used and the applied manual force when pressing the pliers must be taken into account.

When choosing the material for the locking element and the guide pin, the Hertzian stresses and possibly the plastic deformations due to the high clamping forces must be taken into account.

The advantages of the invention are, in particular, to be seen in the fact that the manufacturing costs are considerably reduced in comparison with the prior art. On the one hand, the simply shaped and thus inexpensive to produce items are responsible for this, on the other hand, a simplified assembly of the grip pliers is made possible by the reduced total number of parts. By dispensing with the cam for tilting the locking element also a joint in the region of the support lever is saved, which reduces the cost and increases the durability of the pliers.

Decisive for the dimensioning of the locking element are the dimensions of the effective axial length of the guide surface and the vertical distance of the point of application of the support lever of the guide surface.

In a particularly preferred embodiment of the invention, the locking element comprises an adjustment for the point of application of the support lever. Due to the adjustment of the point of application can preferably be moved on an axis which is arranged parallel to the guide pin.

Furthermore, the support lever is preferably pivotally mounted in a fork support, which is displaceable as part of the locking element within the locking element along a displacement path using the adjustment. This ensures that the point of application of the support lever on the locking element, and thus the length of the effective guide surface, can be changed, whereby an adjustment of the holding force of the grip pliers is made possible in a simple manner.

The Verstellmoglichkeit is preferably formed by an adjusting screw, with which the displacement along the longitudinal axis of the locking element and parallel to the guide pin can be done. But it is also possible to make the adjustment on a curved curve and thus to change both the effective length of the Fuhrungsfläche and the vertical distance of the point of application to the guide surface.

Particularly preferably, the automatic grip pliers also includes a release lever for opening the grip pliers. This is preferably designed so that it engages between the support lever and the movable hand lever to release the overstretched toggle.

The described automatic locking mechanism is particularly suitable for use on the automatic grip pliers, but is also applicable to other hand tools.

A preferred embodiment of the invention will be explained in more detail with reference to FIGS.

Show it:

1 an automatic locking pliers according to the invention with a locking mechanism;

2 : a locking element of in 1 illustrated automatic grip pliers; and

3 : the locking element according to 2 in tilted condition.

1 shows an automatic locking pliers according to the invention with a fixed pliers part 01 holding a first jaw 02 and a firm grip 03 includes. In the fixed pliers part 01 is a second forceps jaw 04 pivotable about a first pivot point 06 (eg formed as a rotation axis) stored. A tension spring (not shown) can be placed between the second jaw 04 and the fixed pliers part 01 for opening the jaws 02 . 04 be provided. A movable / swiveling handle 07 is about a second pivot 08 swiveling in the second Zangebacke 04 stored.

A support lever 09 is at its first end at a third pivot point 11 in the movable handle 07 articulated. The second end of the support lever 09 is in a fourth pivot 12 articulated with a locking element 13 (see also 2 . 3 ) connected. The support lever 09 forms in a known manner with the section between the fulcrums 08 and 11 of the handle 07 a toggle.

The locking element 13 is on a guide pin 14 which is within the Extension of the solid handle 03 preferably in two counter bearings 15 is fixed, slidably arranged. The locking element 13 is due to the force of a compression spring, not shown, which on the guide pin 14 is provided, in the direction of the first jaws 02 crowded.

On the movable handle 07 is a release lever in a known manner 16 provided, when actuated in the direction of the fixed handle 03 the angle between the movable handle 07 and the support lever 09 and thus the hyperextension of the toggle mechanism is released.

In the 2 and 3 are the locking element 13 and its mode of action is shown in more detail. The locking element 13 has a substantially hollow cylindrical guide part 17 on, whose lateral surface 18 on an axial end portion 19 through an opening 25 is open. Over the axial length of the end portion 19 is inside a guide hole 20 thus an at least semi-cylindrical guide surface 21 formed, which the axial guidance of the untilted locking element 13 on the guide pin 14 serves.

A leadership section 22 in which the lateral surface 18 is closed, surrounds the guide pin 14 Completely. In the area of the Fuhrungsabschnittes 22 are in the axially extending guide opening 20 of the leadership part 17 a first step 23 and one or more second stages 24 provided when tilting the locking element 13 each have a plant lines to increase the clamping force in the lock. At the same time forms the first stage 23 which are on the same longitudinal side as the fulcrum 12 is located, a tipping point for the locking element 13 while the second stage or more stages 24 limit the tilt angle. The several stages 24 prevent by a distribution of tensile stress when tilting a "tearing" of the lateral surface.

A lever force F _H is through the Stutzhebel 09 in the fourth pivot 12 on the locking element 13 initiated. As long as the extension line of the lever force F _H the Fuhrungsfläche 21 cuts, becomes the locking element 13 against the guide surface 21 urged and along the guide pin 14 shifted in the direction of the y component of the force. The angle of the force action direction, ie the angle α between the guide surface 21 and the direction of leverage F _H is getting smaller. Once the line of extension of the lever force F _H the guide surface 21 no longer cuts, tilts the locking element 13 around the tipping point forming the first stage 23 and comes with the guide pin 14 in the area of the second stages 24 jammed (see 3 ).

The skilled artisan easily recognizes that in the dimensioning of the locking element of the vertical distance a of the fourth pivot point 12 from the guide surface 21 , as well as the effective axial length l of the guide surface 21 for the inventive function of the locking element 13 are of importance. A good tilting and clamping locking element 13 For example, with a ratio l / a between 1.5 and 4; more preferably between 2 and 3 are prepared.

In the illustrated particularly preferred embodiment of the invention, the locking element comprises 13 an adjustment for the clamping force. This is a fork support 26 provided, which along the longitudinal axis of the locking element 13 is slidably mounted. The fourth pivot 12 is as a bearing for the support lever 09 in the forklift 26 educated. The fork support 26 is preferably U-shaped and by a set screw 27 in their position within the locking element 13 adjustable. By this adjustment, the position of the support lever 09 and thus set the achievable clamping force.

Decisive for the achievable tilt angle β are a height b in the region of the Fuhrungsabschnittes 22 and the diameter D of the guide opening 20 and the diameter d of the guide pin 14 , As effective, a tilt angle β of> 7 ° has been found.

LIST OF REFERENCE NUMBERS

01

fixed pliers part

02

first jaw

03

solid handle

04

second forceps jaw

05

06

first fulcrum

07

movable / swiveling handle

08

second pivot

09

support lever

10

11

third pivot

12

fourth pivot

13

locking element

14

guide pins

15

thrust bearing

16

release lever

17

guide part

18

lateral surface

19

end

20

guide opening

21

guide surface

22

guide section

23

first stage, tipping point

24

second stage (s)

25

opening

26

fork support

27

screw

Claims (10)

Automatic grip pliers with - a fixed pliers part ( 01 ) with a first jaw ( 02 ) and a fixed handle ( 03 ); - one on the fixed pliers part ( 01 ) pivoting second jaw ( 04 ) with a swivelable handle ( 07 ); - a support lever ( 09 ), which between the handles ( 03 . 07 ) hinged, and which is connected to an upper portion of the pivotable handle ( 07 ) forms a toggle lever; and - a locking element ( 13 ), which in the direction of the longitudinal axis of the fixed pliers part ( 01 ) on a guide pin ( 14 ) by means of an axially continuous guide opening ( 20 ), which in a leadership part ( 17 ) of the locking element ( 13 ) is provided, slidably mounted and articulated with the support lever ( 09 ), wherein the locking element ( 13 ) by tilting over a tipping point ( 23 ) relative to the guide pin ( 14 ) is lockable; characterized in that a lateral surface ( 18 ) of the guide opening ( 20 ) of the management part ( 17 ) on a support lever ( 09 ) opposite longitudinal side of the guide pin ( 14 ) in an axial end section ( 19 ) of the management part ( 17 ) through an opening ( 25 ) is open, from which the guide pin ( 14 ) when tilting the locking element ( 13 ) is receivable; wherein a guide surface ( 21 ) at least over the length of the end portion ( 19 ) on the opening ( 25 ) opposite longitudinal side is formed in order to guide the untilted locking element ( 13 ) on the guide pin ( 14 ) to ensure; and wherein a guide section ( 22 ) of the guide opening ( 20 ) with its lateral surface ( 18 ) the guide pin ( 14 ) surrounds the tilting of the locking element ( 13 ) to limit. Automatic grip pliers according to claim 1, characterized in that the guide opening ( 20 ) and the guide pin ( 14 ) have a circular cross section, wherein the guide surface ( 21 ) has an at least semicircular cross-section. Automatic grip pliers according to claim 1 or 2, characterized in that the opening ( 25 ) of the lateral surface ( 18 ) of the management part ( 17 ) starting from the guide section ( 22 ) in the longitudinal direction continuously up to a half cross section of the guide opening ( 20 ). Automatic grip pliers according to one of claims 1 to 3, characterized in that a pivot point ( 12 ) for the articulated mounting of the support lever ( 09 ) a vertical distance a to the guide surface ( 21 ) and that the guide surface ( 21 ) one opposite this fulcrum ( 12 ) has effective length l, wherein the ratio l / a is between 1.5 and 4. Automatic Gripzange according to one of claims 1 to 4, characterized in that a compression spring on the guide pin ( 14 ) is arranged, which the locking element ( 13 ) in the direction of the first jaw ( 02 ) urges. Automatic Gripzange according to one of claims 1 to 5, characterized in that the guide pin ( 14 ) in at least two counter bearings ( 15 ) in the fixed handle ( 03 ) is stored. Automatic Gripzange according to one of claims 1 to 6, characterized in that the locking element ( 13 ) continue to have a fork support ( 26 ) with a pivot point ( 12 ) as a bearing for the support lever ( 09 ), which within the locking element ( 13 ) is displaceable along a displacement path. Automatic Gripzange according to claim 7, characterized in that the displacement of the locking element ( 13 ) guided fork support ( 23 ) by means of a set screw ( 27 ), which in a thread of the locking element ( 13 ) and with the fork support ( 23 ) connected is. Automatic Gripzange according to claim 7 or 8, characterized in that the displacement is straight and parallel to the guide pin ( 14 ) runs. Automatic grip pliers according to claim 7, characterized in that the displacement is a curved curve.

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