EP1824641B1 - Clamping element for workpieces, especially vise - Google Patents

Abstract

This invention relates to a clamping element for workpieces, in particular a vice (10, 33, 40), comprising a first clamping jaw (12, 34, 41) and a second clamping jaw (13, 35, 42), which are mounted on a carriage bed (11). To avoid bending moments as a result of tensile forces acting on the carriage bed (11), the clamping element of the invention is characterized in that the resultants of the forces introduced by the clamping jaws (12, 13, 34, 35, 41, 42) into the carriage bed (11) as a result of the clamping forces acting on the clamping jaws (12, 13, 34, 35, 41, 42) are located in the plane of the neutral fiber (32) of the carriage bed (11). Preferably, the clamping jaws (12, 13, 41, 42) constitute two-armed levers, a clamping surface (21, 24) being associated to the one lever arm and a push rod (27, 46) engaging the other lever arm.

Description

The invention relates to a clamping element for workpieces, in particular vise, with a first clamping jaw and a second clamping jaw, which are mounted on a carriage bed according to the preamble of the independent claim 1, which is known from FR 2559085 is known.

The previous vices generate on mechanical, hydraulic or pneumatic way, a clamping force that is absorbed by the object to be clamped, so generally a workpiece from acting as an abutment jaws. This results in a bending moment on a jaw guiding the clamping jaw, soft must be collected by the rigidity of this carriage bed. This leads to elastic deformations of the carriage bed, which are at the expense of machining accuracy. For highly accurate workpieces it is therefore necessary in the known vises, the carriage bed getting stiffer and harder to build. It should also be taken into account that due to improved tools today higher processing speeds and associated higher machining forces act on the workpiece, which must be absorbed with an increase in the force exerted by the vice clamping force. This increased clamping force in turn requires a larger bending moment.

On this basis, the problem is based on creating a tensioning element, in particular a vice, in which a bending moment is avoided on the carriage bed due to the design.

In the case of the tensioning element according to the invention, the resultant forces resulting from the clamping forces acting on the clamping jaws are forces introduced by the clamping jaws into the carriage bed in the plane of the neutral fiber of the carriage bed.

When clamping a workpiece results in a power circuit from the workpiece on the jaws and the carriage bed due to the clamping forces. It is now ensured that the case initiated in the carriage bed force is in the plane of the neutral fiber of the carriage bed. As a result, only pure tensile or compressive forces in the longitudinal direction of the carriage bed become effective in the carriage bed. A bending moment on the carriage bed no longer occurs.

The introduction of force into the carriage bed according to the invention can be achieved according to the invention in that the first clamping jaw and / or second clamping jaw are supported by a respective hinge pin on a carriage bed, wherein holes for the hinge pins are arranged in a neutral fiber of the carriage bed. This reduces the lever arm, with the forces are introduced due to the clamping forces in the carriage bed to zero, so that a bending moment is completely avoided. Depending on whether the jaws are designed as a one-armed lever or as a two-armed lever, only pressure or tensile forces on the carriage bed arise. Accordingly, the actuator exerts tensile or compressive forces on the jaws.

The clamping jaws are preferably designed as two-armed lever, wherein in each case one lever arm, a clamping surface is associated and the other lever arm acts on a push rod. The tensioning device is duplicated as it were on a side of the neutral fiber opposite the workpiece, except that it acts on the push rod instead of the workpiece becomes. If the lever arms on the clamping jaws are the same length, forces on the push rod and the workpiece are the same. In known vices always acts due to the mounting of the fixed jaw and a force component perpendicular to the clamping force on the carriage bed. This is avoided with the development described above. This alone results regardless of the basic idea of the invention, a significant reduction of the force acting on the carriage bed bending moment, so that this development can also be used advantageously independent of the basic idea.

The construction according to the invention also offers a further advantage. Due to the deflection of the carriage bed and also due to the compressive forces on the jaws are in known clamping elements, the jaws "tilt" outward. This was compensated in the known clamping elements by relatively complicated measures, so-called Niederzugelemente or Niederzugbacken. In the tensioning element according to the invention, these measures are no longer necessary, especially when the hinge pins are arranged for the clamping jaws so that there is a downward movement component on the clamping surfaces.

As actuator can preferably serve a pressure cylinder. Also, a toggle mechanism, spindle drives or other mechanical, hydraulic, pneumatic or magnetic solutions are conceivable.

The known vices are operated in part via an external hydraulic supply directly with pressure medium. In addition, however, vices are used in which by means of a spindle, a hydraulic piston is actuated. The jaw is then assigned a piston of larger diameter. As a result, the force exerted by the spindle force is amplified in the ratio of the surfaces of the two pistons and provided as a clamping force. Such vices are also referred to as vices with hydraulic power amplification.

When vices with hydraulic power boost, but also with directly hydraulically driven vices, the available clamping force or force transmission is limited by the hydraulic pressure and the available space for the piston surfaces.

The clamping element according to the invention has to avoid the disadvantage described above according to a development in addition to a first pressure medium cylinder which actuates one of the two clamping jaws, via a further pressure medium cylinder, which actuates the respective other clamping jaw.

The second jaw thus has its own pressure medium supply and in turn unfolds a clamping force in addition to the clamping force of the first jaw. The total clamping force is thus increased by the clamping force available by the second clamping jaw.

Preferably, the further pressure medium cylinder is hydraulically or pneumatically coupled to the first pressure medium cylinder. It only needs a single pressure medium supply to be provided. In addition, the same pressure medium pressure results at both pressure medium cylinders. So it is structurally the easiest, if the other pressure medium cylinder and the first pressure medium cylinder are connected to each other via a bypass line. This solution is particularly suitable for vices with hydraulic power amplification, in which the spindle force is converted into the pressure medium pressure for the first and the other pressure medium cylinder. If then the piston surfaces of the first pressure medium cylinder and the further pressure medium cylinder are identical, the same clamping forces arise for both clamping jaws.

The further pressure cylinder is preferably arranged in a carriage bed of the clamping element. In practice, sled beds are U-shaped profiles, on the upper sides of the jaws are performed. In the carriage bed is below the jaws sufficient space available to accommodate the further pressure cylinder, so that the overall size of the clamping element does not change.

Further features of the invention relate to constructive embodiments of the clamping element.

Fig. 1

ein erstes Ausführungsbeispiel eines Spannelementes, nämlich einen Schraubstock, mit den Erfindungsmerkmalen in perspektivischer Darstel- lung,

Fig. 2

den Schraubstock gemäß Fig. 1 in Rückansicht,

Fig. 3

den Schraubstock gemäß Fig. 1 in Seitenansicht,

Fig. 4

den Schraubstock gemäß Fig. 1 in Draufsicht,

Fig. 5

den Schraubstock gemäß Fig. 1 in einer Schnittdarstellung in der Ebene V-V gemäß Fig. 2,

Fig. 6

ein zweites Ausführungsbeispiel eines Spannelementes, nämlich einen Schraubstock, mit den Erfindungsmerkmalen im Längsschnitt,

Fig. 7

ein weiteres Ausführungsbeispiel eines Spannelementes, nämlich einen Schraubstock, mit den Erfindungsmerkmalen im Längsschnitt.

The invention will be explained with reference to an embodiment shown in the drawing. Show it:

Fig. 1

A first embodiment of a clamping element, namely a vise, with the features of the invention in perspective representation,

Fig. 2

the vise according to Fig. 1 in rear view,

Fig. 3

the vise according to Fig. 1 in side view,

Fig. 4

the vise according to Fig. 1 in plan view,

Fig. 5

the vise according to Fig. 1 in a sectional view in the plane VV according to Fig. 2 .

Fig. 6

A second embodiment of a clamping element, namely a vise, with the features of the invention in longitudinal section,

Fig. 7

a further embodiment of a clamping element, namely a vise, with the features of the invention in longitudinal section.

In the in the FIGS. 1 to 5 This vice 10 has a carriage bed 11 and a "fixed" jaw 12 and a movable jaw 13. In this case, the "fixed" jaw 12 is only to the extent that it is not confirmed when clamping a workpiece directly over a longer way, which will become apparent from the following description.

When the jaw 13 is a jaw with hydraulic power boost. By means of the spindle 14, the clamping jaw 13 as long as moved up to the workpiece until it comes to rest against the workpiece. Then, the spindle 14 exerts only a pressure on a hydraulic fluid in a hydraulic cylinder 15, which in turn acts on a further piston surface within the clamping jaw 13 in a manner known per se. The jaw 13 has a connection option for an external hydraulic line. This is already the case with the prior art in order to be able to connect the present clamping jaw 13, if necessary, to an external hydraulic line. At this hydraulic connection via a hydraulic fitting 16, a bypass line 17 is connected. Below the clamping jaw 13, a further pressure medium cylinder 18 is provided, which is acted upon by the pressure medium via the bypass line 17, which is connected via a further hydraulic connection 19 to the further pressure medium cylinder 18.

The clamping jaw 13 is designed as a two-armed lever and held by a hinge pin 20 on the carriage bed 11. The upper lever arm of the clamping jaw 13 is connected to the pressure medium cylinder 15 and the spindle 14 and a pressure plate 21 for clamping the workpiece. At the lower lever arm of the Clamping jaw 13 is a cylinder bore 22 of the further pressure medium cylinder 18 is provided, in which a piston 23 is guided.

The second clamping jaw 12 is also designed as a two-armed lever, wherein the upper lever arm carries a pressure plate 24 for clamping the workpiece. The clamping jaw 12 is in turn connected via a hinge pin 25 hingedly connected to the carriage bed 11. At the lower lever arm, a push rod 27 is attached via a hinge pin 26, which in turn is actuated by the piston 23 of the further pressure medium cylinder 18.

In order to adjust the span of the vise 10, holes 29 are provided in the carriage bed 11 in a conventional manner. Accordingly, 27 holes 30 are also provided in the push rod, so that in each case by repositioning the hinge pin 25 and 26, the clamping jaw 12 is offset and so the span of the vise can be adjusted. Further, in the carriage bed 11, one of the number of holes 30 in the push rod 27 corresponding number of holes 31 is provided whose diameter is dimensioned larger by a sufficient amount than the diameter of the hinge pin 26, so that it is free upon actuation of the push rod 27 in the respective Can move holes 31. Alternatively, a slot may be provided in this area in the carriage bed 11.

The hinge pins 25 and 26 are arranged on the outside, as the clamping surfaces 21 and 24. When clamping the workpiece therefore result on the clamping surfaces 21 and 24 on the carriage bed 11 directed movement components that exert a Niederzugeffekt on the workpiece to be clamped.

The vise 10 described so far works as follows. The pressure plate 21 is first brought into contact with the workpiece by operating the spindle 14. Then, the first hydraulic piston 15 is effective and effected the power amplification of the clamping force. At the same time, the hydraulic pressure generated in the first pressure medium cylinder 15 is guided via the bypass line 17 to the further pressure medium cylinder 18, so that the push rod 27 actuates the second clamping jaw 12 via the hinge pin 26. The pressure plate 24 also tilts against the workpiece and in turn unfolds a by the pressure in the pressure cylinder 18 and the piston surface of the piston 23 and the ratio of the lever arms on the clamping jaw 12 certain compressive force or clamping force on the workpiece.

Another special feature of the vise shown is that the holes 29 in the neutral fiber 32 (based on the area moment of inertia) of the carriage bed 11 are arranged. As a result, no bending forces are introduced into the carriage bed 11. Rather, the carriage bed 11 is charged only to train. The clamping surfaces 21, 24 on the one hand and the push rod 27 on the other hand are arranged opposite sides of the neutral fiber 32.

Alternatively to the mechanical actuation via the spindle 14, the clamping force can also be applied via an external hydraulic supply. For this purpose, an additional connection for the external hydraulic supply is provided at a suitable location, for example on the bypass line 17.

Fig. 6 shows an embodiment of a vise 33, in which the clamping jaws 34 and 35 are formed as a one-armed lever and are mounted on the carriage bed 11 via joints 36, 37. The joints 36, 37 are again arranged in the neutral fiber 32. The clamping jaws 34, 35 are actuated via tie rods 38 running parallel to the neutral fiber 32 and which are pulled together by means of a pressure medium cylinder 39.

The in Fig. 7 The one vice 41 is hinged to the carriage bed 11, wherein the joint 43 is again in the neutral fiber 32 of the carriage bed 11. The other jaw 42 is mounted on the carriage bed 11 via a pressure medium cylinder 44, the actuating direction of which is arranged in the neutral fiber 32 and which engages by means of a joint 45 on the clamping jaw 42, which again lies in the neutral fiber 32. The clamping jaws 41, 42 are designed as two-armed lever, wherein each of the one lever arm, the clamping surface 21, 24 is associated. At the other lever arm, the clamping jaws 41, 42 coupled to each other via a parallel to the neutral fiber 32 extending push rod 46. The push rod 46 is, as in the embodiment according to Fig. 1 to 5 on the clamping surfaces 21, 24 opposite side of the neutral fiber 32nd

Of course, it is according to the embodiments 6 and 7 also possible, two clamping jaws 34, 35 and 41, 42 each own pressure medium cylinder assigned.

LIST OF REFERENCE NUMBERS

10

vice

11

sleigh bed

12

jaw

13

jaw

14

spindle

15

Pressure cylinder

16

Hydraulikverschraubung

17

bypass line

18

Pressure cylinder

19

Hydraulikverschraubung

20

hinge pins

21

printing plate

22

bore

23

piston

24

printing plate

25

hinge pins

26

hinge pins

27

pushrod

28

Free

29

drilling

30

drilling

31

drilling

32

Neutral fiber

33

vice

34

jaw

35

jaw

36

joint

37

joint

38

pull bar

39

Pressure cylinder

40

vice

41

jaw

42

jaw

43

joint

44

Pressure cylinder

45

joint

Claims (10)

1. A clamping element for workpieces, in particular a vice (10, 33, 40), comprising a first clamping jaw (12, 34, 41) and a second clamping jaw (13, 35, 42), which are mounted on a carriage bed (11), wherein the resultants of the forces introduced by the clamping jaws (12, 13, 34, 35, 41, 42) into the carriage bed (11) as a result of the clamping forces acting on the clamping jaws (12, 13, 34, 35, 41, 42) are located in the plane of the neutral fibre (32) of the carriage bed (11), characterized in that the first clamping jaw (12, 34, 41) and/or the second clamping jaw (13, 35, 42) are supported on a carriage bed (11) by means of one pivot pin (20, 25; 36, 37; 43, 45) each, the bores (29) for the pivot pins (20, 25; 36, 37; 43, 45) being arranged in a neutral fibre (32) of the carriage bed (11).
2. The clamping element as claimed in claim 1, characterized in that the clamping jaws (12, 13, 41, 42) constitute two-armed levers, a clamping surface (21, 24) being associated to the one lever arm and a push rod (27, 46) engaging the other lever arm.
3. The clamping element as claimed in claim 2, characterized in that the lever arms are of equal length.
4. The clamping element as claimed in any of claims 1 to 3, characterized in that an actuating member, in particular a pressure-fluid cylinder (15, 44), is supported on one of the clamping jaws (12, 13), preferably on the first clamping jaw (12), and the other clamping jaw (13) is actuated by means of a push rod (27, 46).
5. The clamping element as claimed in claim 4, characterized in that the actuating member is a pressure-fluid cylinder (15, 46).
6. The clamping element as claimed in claim 5, characterized in that the first clamping jaw (12) is actuated by means of a first pressure-fluid cylinder (15) and the second clamping jaw (13) has associated thereto a further pressure-fluid cylinder (18).
7. The clamping element as claimed in claim 6, characterized in that the further pressure-fluid cylinder (18) is hydraulically or pneumatically coupled to the first pressure-fluid cylinder (15).
8. The clamping element as claimed in claim 6 or 7, characterized in that the first and the further pressure fluid cylinders (15, 18) are connected with each other by means of a bypass conduit (17).
9. The clamping element as claimed in any of claims 6 to 8, characterized in that the first pressure-fluid cylinder (15) and the further pressure-fluid cylinder (18) have identical piston diameters.
10. The clamping element as claimed in any of claims 6 to 9, characterized in that the further pressure-fluid cylinder (18) is arranged in the carriage bed (11).

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