EP0196544B1 - Vise for precise holding of a workpiece - Google Patents

Abstract

1. A screw vice comprising a bed (3), above which rises a first stationary clamping jaw (4) having a first clamping plate (44), and comprising a second clamping jaw (6; 6') which is movably guided on the bed (3) and which rises above the bed and which has a second clamping plate (73; 73') and which is rotatably connected to a spindle (94) rotatably secured to the bed, wherein the spindle extends in a longitudinal channel (7) provided in the bed and in the longitudinal channel is embraced by a foot portion (61) of the second clamping jaw (6), the foot portion being connected to the second clamping plate (73, 73') by way of a neck portion (67) which is captured in a longitudinal slot (8) in the bed (3), characterised in that a flat reference surface (50, 52) which extends transversely with respect to the clamping plates (44, 73, 73') and between same is provided on relatively thin side walls (72, 74) of the bed (3), which define the longitudinal channel (7), that provided at the side walls are at least two adjacent clamping surfaces (62, 64; 62', 64') which extend in the direction of the reference surface and of which a first clamping surface (62, 62') is inclined relative to the reference surface (50, 52) and the second clamping surface (64, 64') is oppositely inclined relative to the reference surface, and that provided on the second clamping jaw (6, 6') are at least two clamp surfaces (66, 68; 66', 68') which are adjacent to the clamping surfaces and of which the first clamp surface extends parallel to the first clamping surface and the second clamp surface extends parallel to the second clamping surface.

Description

Vice for the precise holding of a workpiece.

The invention relates to a vice with a bed over which a first fixed, a first clamping plate having clamping jaw rises, and with a second, movably guided on the bed, rising above the bed, a second clamping plate having clamping jaw, with a on the bed rotatably mounted spindle is rotatably connected, the spindle extending in a longitudinal channel formed in the bed, and in the longitudinal channel is surrounded by a foot of the second clamping jaw, which is connected to the second clamping plate via a neck captured in a longitudinal slot of the bed. The vice is suitable for holding a precisely aligned workpiece in a machine tool, in particular relative to the cutting wire of a wire cutting spark erosion machine.

For the precise machining of a workpiece in a spark erosion machine, it is necessary for the workpiece, into which a predetermined structure is to be cut, to be held firmly against the bed of the vice. When tightening the jaws against the workpiece, however, it tends to stand out slightly from the bed. This uncontrolled movement of the workpiece during the tightening of the clamping jaws prevents the workpiece from being machined from being precisely aligned relative to a predetermined reference.

Wire cutting spark erosion machines have the peculiarity compared to other machine tools that the working area in which the workpiece can be held in front of the cutting wire is limited. This working area is usually limited on the one hand by a feed device for the cutting wire and on the other hand by the receiving device for the used cutting wire. If a workpiece is to be held in the work area with a vise, it is therefore necessary for the vise to take up as little space as possible within the work area.

A vice with a clamping jaw is known from US Pat. No. 4,411,415, in which the clamping plate is connected to the head of the clamping jaw via connecting members. These connecting links are directed obliquely downwards onto the bed of the vise and serve to hold the workpiece on the bed when the clamping jaws are tightened against the workpiece.

This vice, intended for boring mills, is of a very massive construction and is therefore not suitable for use in the work area of a wire cutting spark erosion machine. In addition, the connecting links are designed such that they are the cause of considerable alignment deviations of the workpiece. The use of articulated connecting links is prohibited in spark erosion machines because the inevitable play in the joints prevents the tolerances in the alignment of the workpiece from being observed.

Document US-A-3,089,708 explains a chuck for a lathe or the like machine tool in which a plurality of collets are radially movable. Each collet consists of a clamping slide guided radially in the chuck, in which the foot of a clamping jaw can move longitudinally when its screwing is loosened with the part of the clamping jaw rising above the clamping slide. When tightening the screw connection between the upper part and the foot, wedges provided on the side of the foot engage in corresponding angular grooves in the side cheeks of the slide and firmly clamp the clamping jaw on the clamping slide, while at the same time avoiding lateral buckling of the slide. Due to the firm clamping of the clamping jaw with the clamping slide, the forces occurring when clamping a tool are transferred directly to the clamping slide, which is supported in its guidance in the chuck.

The interaction of the mentioned wedges with the angular grooves has the purpose in the chuck according to US-A-3 089 708 to prevent the clamping slide from jamming in the chuck.

The invention, on the other hand, is intended to create a vice which allows a workpiece to be held precisely relative to a predetermined reference and also has a construction which is as light as possible so that it can hold workpieces ready for processing by a wire-cutting spark erosion machine over a relatively large dimensional range .

For this purpose, the invention provides that a flat reference surface extending transversely to the clamping plates and between them is formed on relatively thin side walls of the bed defining the longitudinal channel, that at least two adjacent clamping surfaces extending in the direction of the reference surface are formed on the side walls, of which a first clamping surface is inclined relative to the reference surface, and the second clamping surface is inclined in opposite directions relative to the reference surface, and that at least two clamping surfaces adjacent to the clamping surfaces are formed on the second clamping jaw, of which the first clamping surface is parallel to the first clamping surface and the second clamping surface extends parallel to the second clamping surface.

The engagement of the clamping surfaces in the clamping surfaces when clamping a workpiece on the reference surface of the bed by means of the clamping jaws prevents the side walls of the vice, which define the reference surface as well as the slot and the longitudinal channel, from evading laterally under the action of the forces that occur. This makes it possible to choose a very flat design for the bed with relatively thin side walls defining the slot and the longitudinal channel. The Flat design has the advantage of a small footprint, so that the invention is particularly suitable for holding a workpiece precisely in the working area of a wire-cutting spark erosion machine.

In a first embodiment of the invention, the longitudinal channel has at least two parallel grooves, each of which is provided with one of the clamping surfaces, the foot having two parallel projections, each of which is provided with one of the clamping surfaces. The clamping surfaces and clamping surfaces are directed outwards and upwards. The wedge-shaped engagement of clamping surfaces in clamping surfaces holds the relatively thin-walled bed together in such a way that the reference surface remains flat.

If, in a further development, the longitudinal channel has a rectangular cross section that is larger than that of the slot, the grooves can be formed at the transition from the slot to the longitudinal channel.

According to another embodiment of the invention, the clamping surfaces can be formed on both sides next to the reference surface, the head of the second clamping jaw then having lateral tongues on which the clamping surfaces are formed. When clamping a workpiece, the bed of the vise is pressed together from above by tightening the second clamping jaw and held in alignment, since the clamping surfaces and clamping surfaces are directed outwards and downwards. The tongues can expediently be formed on the clamping plate.

With particular advantage with regard to the exact alignment of the workpiece being held, in a further development of the invention at least one of the clamping plates can be connected to the head of the associated clamping jaw via parallel elastic bridges, the bridges being directed obliquely downwards onto the bed. It proves to be advantageous if the clamping plate with head and bridge are made from one piece, since the required dimensional accuracy of the workpiece holder is then ensured.

From FR-A1-432 219 it is generally known that an infeed of a machine part can be achieved by an elastically deformable element which can be pressurized and which is interposed between a solid base and an arm connected to the base via an elastically deformable web. In a preferred development of the invention, however, the vise has a leveling device for the reference surface, which has the shape of at least one open slot which is cut into the flesh of the plate from a side edge of a plate forming the bed and extends essentially parallel to the reference surface. It proves to be expedient if a lug which delimits an expansion of the slot is formed on the plate. Furthermore, in a preferred embodiment of the invention, an adjustable stop which limits the compression of the slot can be provided. If the reference surface experiences a bend when clamping a workpiece, this can be compensated with the leveling device. The slot expediently ends in front of the center of the plate, so that another, similar slot can be cut into the meat of the plate from the opposite side of the plate.

• Fig. 1: eine Draufsicht auf einen Schraubstock gemäß der Erfindung mit gestrichelt angedeutetem Werkstück;
• Fig. 2: eine Seitenansicht des Schraubstocks nach Fig. 1;
• Fig. 3: eine Draufsicht auf das Bett des Schraubstocks, wobei einzelne Teile weggebrochen sind;
• Fig. 4: eine Seitenansicht ähnlich der Fig. 2 des Bettes nach Fig 3;
• Fig. 5: eine Seitenansicht der zweiten Spannbacke, wobei Teile weggebrochen sind;
• Fig. 6: eine Stirnansicht der zweiten Spannbacke nach Fig. 5, von links gesehen;
• Fig. 7: eine Stirnansicht ähnlich der Fig. 4 einer anderern Ausführungsform der Erfindung;
• Fig. 8: eine der Fig. 6 ähnliche Ansicht einer zweiten Ausführungsform der zweiten Spannbacke;
• Fig. 9: eine Seitenansicht der zweiten Spannbacke gemäß der anderen Ausführungsform der Erfindung;
• Fig. 10: eine Schnittansicht des Bettes längs der Linie X-X aus Fig 3.
• Fig 11: eine Stirnansicht des Bettes gemäß Fig. 3 von rechts; und
• Fig. 12: eine Draufsicht auf den zusammengebauten Schraubstock nach Fig. 1;

The invention is described below with reference to the embodiments shown in the accompanying drawings. Show it.

• 1: a plan view of a vice according to the invention with a workpiece indicated by dashed lines;
• Fig. 2 is a side view of the vise of Fig. 1;
• 3 shows a plan view of the bed of the vise, with individual parts broken away;
• 4 shows a side view similar to FIG. 2 of the bed according to FIG. 3;
• 5 shows a side view of the second clamping jaw, with parts broken away;
• FIG. 6: an end view of the second clamping jaw according to FIG. 5, seen from the left;
• FIG. 7: an end view similar to FIG. 4 of another embodiment of the invention;
• 8: a view similar to FIG. 6 of a second embodiment of the second clamping jaw;
• 9 shows a side view of the second clamping jaw according to the other embodiment of the invention;
• 10 shows a sectional view of the bed along the line XX from FIG. 3.
• 11: an end view of the bed according to FIG. 3 from the right; and
• FIG. 12: a top view of the assembled vice according to FIG. 1;

1, 2 and 12 has a base plate 3, which forms a bed of the vice, which has a substantially rectangular shape and is made of tool steel.

The base plate 3 has substantially flat outer surfaces. In the embodiment of the invention shown in the drawing, one dimension of the base plate is very much smaller than the others, so that the base plate 3 is very thin in a side view and in a top view (FIGS. 2, 12) compared to the known vice.

A thick, solid mounting block 2 extends from the underside 30 of the base plate 3, through which a plurality of mounting holes 32, 34, 36, 38 extend. The holes allow the vice to be fastened to a base (not shown) by means of bolts or the like. The base plate 3 and the mounting block 2 consist of one piece.

On the top 5 opposite the bottom 30, two tracks 50, 52 are formed which extend in the longitudinal direction of the bed and parallel to one another. The two tracks 50, 52 are exactly flat and lie in a common plane. The tracks 50, 52 can therefore be used as a reference surface for setting up a rectangular workpiece 25 in a wire cutting spark serve rosion machine (not shown). The workpiece 25 is indicated by dashed lines in FIG. 1.

A fixed jaw 4 rises above one end of the top 5 of the base plate 3. The fixed jaw 4 has a head 42, the side surfaces of which are extensions of the adjacent surfaces of the base plate 3. A first clamping plate 44 is connected via two parallel first bridges 46, 48 to that end face 49 of the first clamping jaw head 42 which points to the tracks 50, 52. Each of the first bridges 46, 48 has the same width as the first jaw head 42 and the first clamping plate 44 and extends downward from the end face 49 at an acute angle. Thus, the first clamping plate 44 is held slightly above the adjacent end of the tracks 50, 52, namely slightly above their common plane. The first clamping plate 44 and the first bridges 46, 48 and the first clamping jaw head 42 are cut from a single piece of metal.

Between the tracks 50, 52, a longitudinal slot 8 is cut into the bed of the base plate 3, which is defined according to FIGS. 4, 10 and 11 by two opposite wall sections 82, 84 of the base plate 3, the inner surfaces of which are parallel to the opposite outer surfaces 35, 37 of the base plate 3 extend.

A longitudinal channel 7 of substantially rectangular cross-section is cut into the bed immediately below the slot 8, which communicates with the longitudinal channel 7, so that the longitudinal channel 7 opens into the reference surface through the longitudinal slot 8. The wall sections 72, 74 that define the longitudinal channel 7 are thinner than the upper wall sections 82, 84, and the inner surfaces 76, 78 of these wall sections 72, 74 run parallel to the corresponding outer surfaces 35, 37 of the base plate 3. At each transition from the inner surfaces 86, 88 of the upper wall sections 82, 84 to the inner surfaces 76, 78 of the wall sections 72, 74 a wedge is formed which is directed into the interior of the longitudinal channel 7 and which is provided with clamping surfaces 62, 64 which are outwardly and with respect to the reference surface are inclined at the top.

The vice according to the invention comprises a second clamping jaw (FIGS. 5 and 6). The second clamping jaw 6 has a foot 61, the cross-sectional shape of which is adapted to the cross-sectional shape of the longitudinal channel 7. The foot 61 thus has opposite side surfaces 63, 65, each of which is intended to slide along the associated, opposite inner surface 76 or 78 of the longitudinal channel 7. The side surfaces 63, 65 are exactly flat and run exactly parallel to one another and perpendicular to sliding surfaces 54, 56, which are formed at the lower end of the head 69 next to and above the neck 67. The foot 61 has the neck 67 which fits into the longitudinal slot 8. The transition from the neck 67 to each of the side surfaces 63, 65 is formed into an outward extension which has clamping surfaces 66, 68, each of which cooperates with one of the clamping surfaces 62, 64 when the foot 61 enters the longitudinal channel 7 and the longitudinal slot 8 is introduced.

The second clamping jaw 6 has a head 69, on the end face 71 of which a second clamping plate 73 is fastened via a pair of parallel second bridges 75, 77. Each of these bridges faces downward toward foot 61.

As can best be seen from FIG. 5, the foot 61 is longer than the head of the second clamping jaw 6 and has a longitudinal bore 79. The front section 81 of the longitudinal bore 79, which is removed from the head 69, has a reduced diameter and an internal thread into which one with an external thread provided spindle 94 (Fig. 12) can engage.

To assemble the vice according to the invention, the spindle 94 is screwed into the front section 81 of the longitudinal bore 79 of the second clamping jaw 6, and the foot 61 together with the spindle 94 is inserted into the longitudinal channel 7 and the longitudinal slot 8, when viewing FIG. 1 from the left forth, introduced so that the clamping plates 44 and 73 assign to each other. The second clamping jaw 6 then rides on the reference surface, that is to say the surfaces 54 and 56 ride on the tracks 52 and 50, respectively. Since the spindle protrudes over the two lateral ends of the base plate 3 from the longitudinal channel, it can be moved in this by one on the End of the spindle 94 firmly attached handle 96 and an intermediate plate 97 are attached, which are placed on the right-hand end of the spindle 94 protruding from the longitudinal channel 7 over the right side of the base plate 3. The opposite end of the spindle is fastened by a pair of nuts 98, 99 and an intermediate washer 100, which are applied to the left end of the spindle 94, which projects beyond the left-hand end of the longitudinal channel (FIGS. 1 and 12).

By turning the handle 96 clockwise or counterclockwise, the spindle 94 rotates accordingly, so that the second clamping jaw slides over the tracks 50, 52.

If, when clamping the workpiece 25, a clamping force is exerted by the second clamping jaw by rotating the handle 96 in one direction, the workpiece 25 is pressed onto the tracks 50, 52 under the action of the bridges 46, 48 and 75, 77. On the other hand, the head 69 of the second jaw is subject to the forces which tend to rotate the head 69 counterclockwise (FIG. 1), whereby the clamping surfaces 66 and 68 engage with the clamping surfaces 62 and 64 and thereby preventing the walls 82, 84 and 72, 74 from bending outwards, which consequently are held parallel to the surfaces 63, 64 of the second clamping jaw 6.

On the other hand, the force that tends to rotate the head 69 of the second jaw 6 counterclockwise when viewing FIG. 1 can cause the webs 50, 52 to slightly deform downward. Such a deviation can result from the leveling device be compared with which the vise according to the invention is equipped.

Thereafter, two slots 15, 16 are provided in the base plate 3, of which a first slot 15 extends from the right side surface 54 and the second slot 16 extends from the opposite side surface 56 of the base plate 3. Each slot 15, 16 completely penetrates the thickness of the base plate and follows a stepped line to a final hole 17 or 18, which is located near the center of the base plate 3. Both holes 17, 18 are arranged symmetrically to the center and are equidistant from the reference surface. The stepped line that each slot 15, 16 follows is designed so that an outwardly extending lug 12 and 13 is created. The slots 15, 16 divide the base plate 3 into an upper section 11 and a lower section 12, which are held together by that part of the base plate which is located between the closing holes. In each outer end 20 or 21 of the lower section 12, an upwardly directed threaded hole 22 (FIG. 3) is cut, into which a set screw 18, 19 is screwed. The upper end face of each of the set screws abuts the opposite underside of the upper section 11. The upper section 11 can be raised slightly by turning one of the two set screws 18, 19. An inwardly directed arm 24, 26 of the upper section engages the associated outwardly extending nose 12 and 13, respectively, so that the abutment of each arm against the associated nose forms a stop for the upward bending of the corresponding part of the upper section 11 of the base plate 3. Therefore, if the reference surface should be curved convexly when clamping the workpiece 25, this deviation can be eliminated by turning the corresponding set screw, whereby the associated part of the upper section is raised slightly and the tracks 50, 52 are aligned in the reference surface.

Figures 7, 8 and 9 show a second embodiment of the invention, which relates to the formation of the clamping surfaces and the clamping surfaces. In this embodiment, each of the webs 50, 52 is provided on its outer longitudinal edge with an outwardly inclined clamping surface 62 ', 64'. Furthermore, the clamping plate 63 'of the second clamping jaw 6' is provided with downwardly extending aprons 75 ', on which clamping surfaces 66', 68 'are formed, which are inclined downwards and outwards with respect to the reference surface.

When a workpiece is to be clamped with the second embodiment of the invention, the downwardly extending skirts abut the downward and outward clamping surfaces and prevent the walls defining the longitudinal slot and the longitudinal channel from bending away from a straight line. In this embodiment of the invention, the wedges at the transitions between the longitudinal slot and the longitudinal channel are omitted. Alternatively, these aprons can be provided on the opposite lower side ends of the head 69 'of the clamping jaw 6'.

Finally, it is within the scope of the invention to mount differently shaped mounting devices on the underside 30 of the base plate. Instead of the mounting block 2, a shaft can be provided which can be clamped in a hydraulic chuck of a spark erosion machine. Depending on the intended use of the vice according to the invention, different fastening devices can be provided instead of the assembly block explained above.

Claims (12)

1. A screw vice comprising a bed (3), above which rises a first stationary clamping jaw (4) having a first clamping plate (44), and comprising a second clamping jaw (6; 6') which is movably guided on the bed (3) and which rises above the bed and which has a second clamping plate (73; 73') and which is rotatably connected to a spindle (94) rotatably secured to the bed, wherein the spindle extends in a longitudinal channel (7) provided in the bed and in the longitudinal channel is embraced by a foot portion (61) of the second clamping jaw (6), the foot portion being connected to the second clamping plate (73, 73') by way of a neck portion (67) which is captured in a longitudinal slot (8) in the bed (3), characterised in that a flat reference surface (50, 52) which extends transversely with respect to the clamping plates (44, 73, 73') and between same is provided on relatively thin side walls (72, 74) of the bed (3), which define the longitudinal channel (7), that provided at the side walls are at least two adjacent clamping surfaces (62, 64; 62', 64') which extend in the direction of the reference surface and of which a first clamping surface (62, 62') is inclined relative to the reference surface (50, 52) and the second clamping surface (64, 64') is oppositely inclined relative to the reference surface, and that provided on the second clamping jaw (6, 6') are at least two clamp surfaces (66, 68; 66', 68') which are adjacent to the clamping surfaces and of which the first clamp surface extends parallel to the first clamping surface and the second clamp surface extends parallel to the second clamping surface.

2. A screw vice according to claim 1 characterised in that the longitudinal channel (7) has at least two parallel grooves which are each provided with a respective one of the clamping surfaces and that the foot portion (61) has two parallel projections, each of which is provided with one of the clamp surfaces.

3. A screw vice according to claim 1 or claim 2 characterised in that the longitudinal channel (7) is of rectangular cross-section which is larger than that of the slot (8) and that the grooves are provided at the transition from the slot to the longitudinal channel.

4. A screw vice according to one of the preceding claims characterised in that the clamping surfaces are provided on both sides beside the reference surface (Figures 7-9) and that the head (69, 69') of the second clamping jaw (6, 6') has lateral tongues (75') on which the clamp surfaces are provided.

5. A screw vice according to one of the preceding claims characterised in that at least one of the clamping plates (44, 73, 73') is connected to the head (42, 69) of the clamping jaw (4, 6) by way of parallel, resilient bridge portions (46, 48; 75, 77) which are inclined with respect to the reference surface.

6. A screw vice according to claim 5 characterised in that the respective clamping plate comprises one piece with the head of the clamping jaw and the bridge portions.

7. A screw vice according to one of claims 4 to 6 characterised in that the tongues are provided on the clamping plate (73').

8. A screw vice according to one of the preceding claims characterised in that there is provided a levelling means for the reference surface (50, 52), which has at least one slot (15, 16) which extends substantially parallel to the reference surface and which is cut in from a side surface (54, 56) of a plate (3) forming the bed, to the middle thereof.

9. A screw vice according to claim 8 characterised in that two oppositely extending slots (15, 16) are cut in from the two oppositely disposed side surfaces (54, 56) of the plate (3).

10. A screw vice according to claim 8 or claim 9 characterised in that the slots (15, 16) are symmetrical with respect to the middle of the plate (3) and each terminate in a respective hole (17, 18).

11. A screw vice according to one of claims 8 to 10 characterised in that the slots follow a stepped line and each form a respective outwardly facing nose portion (12, 13), each of which has a respective inwardly facing arm portion (24, 26) engaging beneath it to form an abutment for limiting expansion of the associated slot.

12. A screw vice according to one of claims 8 to 11 characterised in that a respective adjusting screw (18, 19) is screwed in the two sides of a lower portion (12) of the plate (3) and engages under the associated arm as a means for limiting compression of the associated slot.

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