EP0894573A2 - Workpiece clamp - Google Patents

Abstract

The tension rod (16) is operated pneumatically, hydraulically or electrically and has a tension arm (4) which swivels from its tension position (ST) into a prepared position (BP). A rigid lever (11) is connected rotationally secured to the arm by a swivel shaft (7) and a rigid bracket (13) is coupled both to the lever (11) and to the end of the tension rod. The length (L1) between the coupling joints (12,14) is greater than the distance (A) between the coupling joint (12) of the bracket and lever and the longitudinal axis of the tension rod in the prepared position. The coupling joint (14) between bracket and end of tension rod is supported on a roller (17) which rolls on a compulsory guide (18) having a length section (L) running in a straight line parallel to the longitudinal axis (27) of the tension rod in the prepared position. The guide has an end section (23) which is concave with the coupling joint between lever and bracket in its dead centre and which starts before the plane (E-E) running through the coupling joint (12) in dead centre and extending at right angles to a longitudinal axis of the tension rod in prepared position, and which ends behind this plane.

Description

Component clamps are used in various technical Areas used for the current fixation of workpieces. You have to work quickly and reliably as well Maintenance-free multiple load changes over long periods of use guarantee.

In this context counts through DE 35 28 337 C2 a component clamp to the prior art, in which a tension rod part of a by a pressure fluid, such as air or hydraulic fluid, actable and forms axially displaceable piston in a cylinder. The end of the tension rod facing away from the piston is provided with a Connected bolt that carries two pairs of rollers. The roles of the outer pair of rollers run in straight slots that extend parallel to the longitudinal axis of the tension rod. The roles of the inner pair of rollers run in an arc Slitting a clamping arm that can be pivoted about an axis.

The guide slot may also be curved in an arc shape be.

With this design, uncontrollably high clamping forces are to be achieved avoided with self-locking in the end position become. However, this type of construction requires a complicated one Mechanics with consequent elaborate production. The component clamp builds wide through the guide slot. Because of the direct leverage is a long piston travel and thus a correspondingly elongated design inevitably given. The toggle principle is used here applied in a modified form.

In order for a component clamp according to the toggle principle the self-retention, it is necessary to come up with one Part of the toggle lever arrangement forming tab over to drive to top dead center. The force increases the tab theoretically to infinity. In practice the force is caused by elastic deformations throughout System limited. However, this means wear. Farther cannot be guaranteed that the tension arm in the case of high clamping forces, actually beyond the dead center is pivoted. The maximum tension is determined by the available energy, especially compressed air, certainly. Is this prevailing in an air cylinder Cylinder force is not large enough to meet the requirements Applying clamping forces to the clamping arm drives the Do not tab over the dead center and therefore not in the self-retention.

DE 31 30 942 A1 discloses a component clamp the toggle principle. To the free end of one with one piston rod connected to pressurized medium is a resiliently designed tab articulated, which is also connected to a rigid toggle lever, which is coupled in 90 ° offset with a tension arm.

The tab is designed so that the distance of the Coupling joints changeable with the piston rod and the lever is.

The resilient tab means that the clamping forces are infinite be avoided. With this, however, only that Tension limited, but no self-locking achieved become. In addition, the fatigue strength and durability should be the tab can be problematic. Your manufacturing is also expensive. In addition, the force limit dependent on the spring constant and the spring travel.

The invention is based on the prior art The task is to create a component clamp that with a simple design using the toggle principle allows a limitation of the increase in force and it still ensures that in the clamping position too if the clamping energy fails, the clamping position Self-locking is guaranteed.

The solution to this problem is set forth in claim 1 Characteristics seen.

The essence of the invention is the fact that the Positive guidance for at least one end of the tension rod arranged roller with one to the coupling joint concave between lever and tab in its dead center End section is provided. This concave end section begins just before the level that passes through the coupling joint extends between the lever and the tab if this coupling joint in the through the clamping position of the clamping arm is certain dead center, and ends behind this level.

Reaches the coupling joint between the tab and the Tension rod the beginning of the concave end section At this level, the clamping arm is in the clamping position. The maximum clamping force is built up. It takes place no further increase in strength took place. By at the Clamping rod further pending clamping force will Coupling joint between the bracket and the tension rod over the Moved level until this coupling joint that behind reached the plane end of the concave end section Has. With this movement, the maximum remains Always maintain resilience. The tab lies behind the level in the self-locking area. Falls in this position the clamping energy is gone, but remains complete Preserve resilience without loss.

The particular advantage of the invention is therefore the assurance the force limitation in a simple way the concave end section. This will make a flawless Self-locking after passing dead center guaranteed. The component clamp is also very compact Construction, because of the path translation according to the invention only a little between the lever and the tab Stroke of the tension rod is required.

The invention also allows the pivoting angle of the Between the standby position and the To be able to set up the clamping position as desired. Only through the use of stroke-limiting pieces or through the exchange of the tension rod can open angles of in particular 45 °, 60 °, 90 ° and 115 ° up to a maximum Opening angle of 135 ° can be provided. Furthermore can easily integrate the component clamp Position query can be assigned.

The housing for storing the tension arm, lever, bracket and Tension rod is also designed so that one with the Low-tension abutment to fix the position of the workpieces to be machined releasably assigned to the housing can be.

A particularly useful embodiment of the invention consists in the features of claim 2. Then extends the concave end portion of the positive guidance over a length that the plane through the coupling joint overlapping between the lever and the tab at the dead center Swivel angle of the bracket from 6 ° to 10 °, preferably but 8 °. This is 4 ° above the level ensures the self-locking of the tab.

The concave end portion is preferred according to claim 3 curved in a circular arc. It has a radius, which plus the length of the tab between the coupling joints corresponds to the radius of the roller.

According to the features of claim 4, the positive guidance, the lever, the bracket and the roller in one connectable with the guide for the tension rod two-piece Housing arranged. That way these parts against external influences even in a rough Operation well protected. The two-part design of the housing allows easy manufacture and trouble-free Assembly. The guide is especially a cylinder formed when according to a preferred embodiment the tension rod as with a pressurized air or also with a hydraulic load Piston connected piston rod formed is. The necessary deflection of the tension rod at one Contact of the roller with the concave end portion caught by the seals on the cylinder for the tension rod.

An even tilt-free force transmission from The tension rod on the tension arm comes with the features of claim 5 achieved.

It is particularly useful if according to claim 6 Swivel shaft in the end sections carrying the articulated arms is polygonal. Here the swivel shaft in particular be square. The articulated arms are then with corresponding recesses and / or Provide clamps through which the articulated arms work properly can be fixed on the swivel shaft. The pivot shaft and the lever are preferably a component, which are manufactured by turning and milling operations can.

Figur 1

einen Bauteilspanner in schematischer Seitenansicht;

Figur 2

den Bauteilspanner der Figur 1 in der Draufsicht;

Figuren 3 bis 6

in vergrößerter Darstellung einen vertikalen Längsschnitt durch die Figur 2 entlang der Linie A-A entsprechend dem Ausschnitt B der Figur 1 in vier verschiedenen Betriebsstellungen;

Figuren 7 bis 10

die Darstellungen der Figuren 3 bis 6 im Schema und

Figur 11

in nochmals vergrößertem Maßstab die Darstellung der Figur 9.

The invention is explained in more detail below on the basis of an exemplary embodiment illustrated in the drawings. Show it:

Figure 1

a component clamp in a schematic side view;

Figure 2

the component clamp of Figure 1 in plan view;

Figures 3 to 6

in an enlarged representation a vertical longitudinal section through FIG. 2 along line AA corresponding to section B of FIG. 1 in four different operating positions;

Figures 7 to 10

the representations of Figures 3 to 6 in the scheme and

Figure 11

on a further enlarged scale the illustration of FIG. 9.

With 1 in Figures 1 and 2 is a operated with compressed air Component clamp called. The component clamp 1 comprises a cylinder 2 to which compressed air can be applied to guide a piston, not shown in detail with piston rod, one connected to cylinder 2 two-part housing 3 with an integrated not illustrated toggle lever system for transmission the force exerted by the compressed air on the piston a pivotable tension arm 4. The tension arm 4 has a U-shape Configuration two articulated arms 5, which over Clamping pieces 6 on one led out of the housing 3 Ends square-shaped swivel shaft 7 releasable are attached. In the illustrated in Figures 1 and 2 The clamping position ST runs the longitudinal axis 8 of the clamping arm 4 perpendicular to the longitudinal axis 9 of the cylinder 2. The compressed air connection of the annulus 2a is with 10 and that of the piston chamber 2b is designated 10a.

As can be seen in FIGS. 3 to 6, the tension arm 4 inside the housing 3 a rigid lever 11 connected in 90 ° offset. The lever 11 forms one integral part of the swivel shaft 7.

At the end facing away from the pivot shaft 7 is the lever 11 via a coupling joint 12 with a rigid bracket 13 connected, which in turn via a coupling joint 14 is connected to the end 15 of a tension rod 16 (Figure 3). The coupling joint 14 is supported on a roller 17 from a positive guide 18 in the housing 3 passes on. A recess 19 in the halves 20, 21 of the housing 3 is the size of the pivoting movements of the lever 11 and the tab 13 adapted.

As can be seen more clearly in FIG. 11, sets the positive guide 18 for the roller 17 a straight length 22 and an arcuate curved end portion 23 together. The length L of the straight length section 22 corresponds the size of the pivot angle α of the tension arm 4 between the standby position BP and the clamping position ST. He runs in a straight line parallel to the longitudinal axis 9 of the cylinder 2. The end section 23 is to the coupling joint 12 between the lever 11 and the tab 13 in its dead center (Clamping position ST of 4) concavely curved. It starts with 24 in front of the through the dead center coupling joint 12 extending to the longitudinal axis 9 of the cylinder 2 vertically extending plane E-E and ends at 25 behind this level E-E. Its arc length corresponds to L3 the angle 2β between points 24 and 25. The angle β between the plane E-E and points 24, 25 of the concave end section 23 is 4 ° in each case.

It can also be seen from FIG. 11 that the length L1 the tab 13 between the coupling joints 12 and 14 greater than the distance A between the coupling joint 12 and the coaxial to the longitudinal axis 9 of the cylinder 2 Longitudinal axis 27 of the tension rod 18 is dimensioned.

The operation of the component clamp 1 is as follows explained in more detail with reference to FIGS. 3 to 11.

In Figures 3 and 7, the standby position is BP of the tension arm 4 shown. The opening angle is α 135 °. The component clamp 1 is fully open. It is 10 compressed air in the annulus via the compressed air connection 2a of the cylinder 2.

By acting on the piston 28 in the piston chamber 2b of the This becomes cylinder 2 in the longitudinal direction of cylinder 2 moved (Figures 4 and 8). The roller 17 rolls from the length section 22 of the positive guide 18. Has the Roller 17 the lower end 24 in the drawing plane of the concave end section 23 is reached (FIGS. 4 and 8), the clamping arm 4 is pivoted through 135 ° into the clamping position ST been. The opening angle is 0 °. The maximal Tension is reached.

By further loading the piston 28 with compressed air drives over the compressed air connection 10a of the piston chamber 2b the tension rod 16 further out and pivots the tab 13 around the now fixedly fixed coupling joint 12 between the lever 11 and the tab 13 to the level E-E, which extends through the coupling joint 12 and perpendicular runs to the longitudinal axis 9 of the cylinder 2. Here rolls the roller 17 on the concave end section 23, without increasing the tension already achieved (Figures 5, 9 and 11).

By continuing to apply the piston 28 The flap 13 becomes compressed air according to FIGS. 6 and 10 also moved beyond this level E-E until that the roller 17 the upper end 25 of the concave end portion 23 has reached.

If compressed air now drops, the complete would Tension is retained since the tab 13 is 4 ° over level E-E and is therefore in the area of self-locking located.

List of reference symbols

1 -

Component clamp

2 -

cylinder

2a -

Annulus v. 2nd

2 B -

Piston chamber v. 2nd

3 -

casing

4 -

Arm

5 -

Articulated arms 4th

6 -

Clamps

7 -

Swivel shaft

8th -

Longitudinal axis v. 4th

9 -

Longitudinal axis v. 2nd

10 -

Compressed air connection

10a -

Compressed air connection

11 -

lever

12 -

Coupling joint f. 11 u. 13

13 -

Tab

14 -

Coupling joint between 13 and 15

15 -

End of v. 16

16 -

Tension rod

17 -

Roller

18 -

Positive control

19 -

Recess in 20, 21

20 -

Half of 3rd

21 -

Half of 3rd

22 -

Longitudinal section v. 18th

23 -

End section v. 18th

24 -

Beginning v, 23

25 -

End of v. 23

26 -

Axis v. 7

27 -

Longitudinal axis v. 16

28 -

Piston in 2nd

A -

Distance between 12 u. 27

BP -

Standby position

E-E-

Level through 12

L -

Length of 22

L1 -

Length of 13

L2 -

Length of 11

L3 -

Arc length of 23

R -

Radius of 23

r -

Radius of 17th

ST -

Clamping position v. 4th

α -

Swivel angle v. 4th

β -

Angle between E-E u. 24 or 25

Claims (6)

Component clamp, one by pneumatic, hydraulic or electric energy shiftable tension rod (16), one from its clamping position (ST) in a standby position (BP) and vice versa swiveling tension arm (4), one with the tension arm (4) rigidly connected via a swivel shaft (7) Lever (11) and one with the lever (11) as well also with the end (15) of the tension rod (16) rotatable coupled rigid tab (13), the Length (L1) between the coupling joints (12, 14) greater than the distance (A) between the coupling joint (12) the tab (13) with the lever (11) and Longitudinal axis (27) of the tension rod (16) in the ready position (BP) is dimensioned, the coupling joint (14) between the tab (13) and the end (15) the tension rod (16) on at least one roller (17) is supported on a positive guidance (18) rolls, which a the swivel angle (α) of Clamping arm (4) between the standby position (BP) and the length section corresponding to the clamping position (ST) (L), which is parallel to the straight line Longitudinal axis (27) of the tension rod (16) in the ready position (BP) runs, and which with a to the coupling joint (12) between lever (11) and bracket (13) at its dead center concave end section (23) is provided in front of the one in the dead center located coupling joint (12) extending to Longitudinal axis (27) of the tension rod (16) in the ready position (BP) vertically extending plane (E-E) begins and ends after this level (E-E). Component clamp according to Claim 1, characterized in that the concave end section (23) of the positive guide (18) extends over an arc length (L3) which extends from 6 ° to 6 ° to a swivel angle (2β) of the bracket (13) spanning the plane (EE) 10 °, preferably 8 °, corresponds. Component clamp according to claim 1 or 2, characterized in that the concave end section (23) has a radius (R) which is the length (L1) of the bracket (13) between the coupling joints (12, 14) plus the radius (r) of the Roller (17) corresponds. Component clamp according to one of claims 1 to 3, characterized in that the positive guide (18), the lever (11), the tab (13) and the roller (17) in one with the guide (2) for the clamping rod (16) connectable two-part housing (3) are arranged. Component clamp according to one of claims 1 to 4, characterized in that the tensioning arm (4) with two articulated arms (5) laterally surrounds the housing (3) and via the articulated arms (5) with the ends of the leds out of the housing (3) the lever (11) integrally designed pivot shaft (7) is rotatably connected. Component clamp according to claim 5, characterized in that the swivel shaft (7) is polygonal in the end sections carrying the articulated arms (5).

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