DE4014616A1 - Vice to hold irregular articles for milling - has separate independent radial hydraulically operated jaws - Google Patents

Abstract

The vice to hold irregularly shaped articles for a milling or rotary machine. Separate radial holding jaws (7) are activated by hydraulic cylinders (2) which are connected to a common hydraulic reservoir. A device (14) puts pressure on the reservoir which activates the cylinders and the jaws (7), moving them in towards the work object (15). Cylinders can be individually disconnected from the reservoir, and pressure can be raised in consequence of the penetration of a needle (22) into the reservoir. USE/ADVANTAGE - The jaws can move independently to suit the contour of the object, or the object may be centralized.

Description

The present invention relates to a chuck direction especially for milling or turning machines for Clamping an irregularly shaped workpiece under Use multiple clamping cylinders to hold this workpiece hold motionless during machining. About that in addition, the invention relates to a clamping cylinder as well a method for clamping a workpiece.

Especially with irregularly shaped workpieces it is vital to the workpiece first firmly clamped in the jig and on finally centering the workpiece relative to the Processing unit. With mechanical on In the past, this was only jigs possible with difficulty, since one already turned on clamped workpiece only by changing the position the position of the individual, mechanical clamping cylinders could be changed, which was very expensive. In addition, the clamping was irregular shaped workpieces in both mechanical and hydraulic clamping devices regularly against a rigid surface, with the result that any No more readjustment of the clamped workpiece or was difficult to do.

The object of the invention is a clamping to create device which the biasing a  allows irregularly shaped workpiece, and itself here in particular the individual clamping cylinders Align the contour of the workpiece and / or the workpiece centered in the clamped state d. H. in its position can be changed and then clamping of the workpiece in the aligned or centered Position can be done. The jig should Meeting these requirements is also a have a particularly simple construction.

The above task is preceded by a clamping direction solved, which is characterized in that

• a) the clamping cylinders are operated hydraulically and are arranged so that they are, as it were, an on or a chuck
• b) all clamping cylinders with one and the same Hydraulic reservoir are connected,
• c) a device is provided, which is central Can exert pressure on the hydraulic reservoir whereby the holding links of the individual clamping cylinders be moved towards the workpiece and the workpiece can be biased in this way,
• d) the location of the c preloaded workpiece by the processing unit, for example by means of a mandrel or the like can be centered or is adjustable
• e) the connection of the individual clamping cylinders to Hydraulic reservoir is separable and  
• f) at least one clamping cylinder with a printer elevation pen is equipped, by means of which a Pressure increase as a result of moving the pen in into the hydraulic reservoir of the respective instep cylinder is achievable.

The invention ensures the possibility of any clamp shaped workpieces in a simple way center and then in the centered position to tighten. Prestressing the workpiece, i. H. the Moving the individual holding members is more convenient by operating the main piston. The workpiece is here by the holding links of the individual instep cylinder fixed. Retensioning after centering is advantageously carried out independently of the head cylinder by using a pressure increasing pin. The pressure increase pin ensures one on the workpiece (possibly tons) Contact pressure at comparatively very little (also manually possible) effort to Actuation of the pressure increase pin.

Expediently, the clamping cylinders are particularly suitable special parallel lines with each other as well connected to the device for generating the pressure, the respective separation of the clamping cylinders by Valves, preferably check valves. Will through the respective valve the respective clamping cylinder from Hydraulic reservoir separated, the holding part of the concerned clamping cylinder even with back pressure in Position. Through the individual valves you can current position or position of the workpiece freeze as it were. The clamping cylinder, which with is provided with a pressure increasing pin, causes at Actuation of the pressure increase pin a pressure increase  and thus a clamping of the one in position d. H. preloaded workpiece.

According to a further embodiment of the Clamping device according to the invention - as valves preferably adjustable pressure relief valves is used here in addition to the function of separating the individual Clamping cylinder at the same time by pressing the Specify the maximum pressure that can be achieved by the pressure increase pin.

The pin of the pressure booster expediently has pin one compared to the diameter of the piston of the clamping cylinder to ensure small diameter afford that with as little effort as possible Increasing the pressure on the workpiece can be achieved.

An appropriate design of the present Er is characterized in that the printer elevation pin, preferably via a thread or a Grid or the like is actuated. Through the Possibility of manual clamping of the workpiece by the operator, especially the Un risk of falling, which in known clamping devices due to automatic tightening exists, reduced to a particular extent, since the Be the operator directly by hand can control.

Alternatively, the pressure increase pin can be electro magnetic, preferably via an electromagnet and moved via a potentiometer and thereby the Pressure can be set.

For the rough adjustment of the individual holding links of the Clamping cylinder is either a mechanical one, by hand too  actuating toggle lever, a hydraulic pump or a Pneumatic system provided, these facilities act on one main piston each.

A return spring ensures that when the hydraulic mechanical or pneumatic pressure of the Main piston is pulled back, causing the Retain the links also and the workpiece is released.

The clamping cylinders are expediently circular or hemispherical as it were dome-shaped around the work arranged around. This arrangement ensures the secure clamping of differently shaped works pieces.

A special embodiment of the invention Clamping device is characterized in that a Many, preferably grid-like, distributed instep cylinders of small dimensions are provided, which on Grip the workpiece selectively. This is particularly the case with very sensitive elongated different ge shaped flat parts particularly advantageous because the holding force here is distributed as widely as possible. It be this gives you the option, for example agile, sensitive flat parts with one of the like jig from the two main surfaces to clamp here. This is advantageous Damage to such parts avoided, which at previous devices in which a clamping against there was a firm surface, appeared regularly.

The inventive complex also includes a span cylinders, especially for use in one clamping devices according to claims 1-10. This instep  cylinder is characterized in that the instep cylinder move a cylinder space with one in it Lich arranged pistons, being on both sides the piston of the cylinders with hydraulic fluid fills, both sides of the separated by the piston Cylinder space via one with a valve, in particular Check valve equipped compensation line with each other communicate, and one in the cylinder room Movable pressure increasing pin for pressure fine vote is provided.

The tension cylinder according to the invention allows a simple one in positioning or attaching the holding member to Workpiece. The holding member can, for example, by hand be brought up to the workpiece. A sticking is then carried out by the pressure increase pin. The Use of the pressure increase pen lowers throughout considerable risk of accident when using of the clamping cylinder according to the invention, as in be knew clamping cylinders in which the contact pressure by Overpressure reducing valves was threatened.

The pressure increase pin is expediently manual, preferably via a thread or a grid actionable. The operator can thereby immediately determine the clamping pressure with one hand and with the position the workpiece with another hand, an un hoping to pinch a finger or hand Operator must therefore be completely excluded.

The pressure to be set using the pressure increase pin pressure can be particularly spring-loaded Pressure regulating piston with display scale on the outside of the Clamping cylinders are displayed.  

A particularly simple, self-contained and above also advantageous manageable version of the he inventive clamping cylinder is characterized records that the clamping cylinder with a particular head mechanically driven by a toggle piston is hydraulically connected, the loading ensures a rough movement of the holding part. The holding part can therefore be easily by Be operation of the knee lever can be moved by hand, a Hydraulic pump or the like is not necessary Tensioning cylinder can therefore be relative in its entirety easy to handle.

Instead of a check valve, it can also be useful a pressure relief valve is arranged in the compensation line be at a certain pressure in the hydraulics reservoir opens, d. H. the compensation line releases and thereby ensure an effective pressure limitation accomplishes.

The claims 16-21 relate to another issue design of a clamping cylinder according to the invention, in which an i. w. more fixed, designed as a disc Working piston inside the housing of the clamping cylinder is provided, with a housing insert with an off hydraulic pressure along the piston is axially movable. This type of tension cylinder represents as it were a round vice, the An pressing pressure on the side, protruding from the housing Arms are transferred to clamps or the like can. This clamping cylinder allows a simple and secure clamping of workpieces with an inclined plane surfaces because of the housing insert, which over the arms as well as clamps with the surface of the workpiece in  Connection is established, tilted to a certain extent can be.

Finally, the invention also relates to a method for clamping a tool, especially under Ver application of a clamping device according to the claims 1-10, which is characterized by the following process steps is drawing.

• a) inserting the workpiece and increasing the hydraulic pressure until the stop fully grip the links on the workpiece and hold it with pre-tension,
• b) Centering or aligning the a preloaded workpiece in particular by a processing machine part, for example wise through a centering mandrel,
• c) Close the individual clamping cylinders with valves connecting the hydraulic reservoir, such as
• d) then actuating the pressure increase pins, which clamps the workpiece becomes.

For a better understanding, the following are based on the Drawings useful embodiments of the invention explained in more detail. Show it:

Fig. 1 is a schematic, greatly simplified Dar position of a Einspannvor direction according to the invention;

Fig. 2 is a schematic, greatly simplified Dar position of a clamping cylinder according to the invention in side view and in plan view;

Figure 3 shows a further useful embodiment of the inventive tensioning cylinder using a toggle lever in a highly simplified, schematic representation.

Figure 4 shows a further embodiment of the clamping cylinder according to the invention as a "round screw stock" in a highly simplified schematic representation. such as

Fig. 5 shows the clamping cylinder according to Fig. 4 with the clamped workpiece in side view.

Fig. 1 shows an expedient embodiment of the inventive clamping device. The Einspannvor direction comprises a plurality of clamping cylinders 2, the housing 24 located in a piston 2 'towards each other are arranged directed. Fixing a marked by the numeral 15 on the workpiece is performed with the respective piston 2 'with affiliated retaining members 7 of the individual clamping cylinder. 2

Each clamping cylinder 2 is connected via a hydraulic line 4 , 4 'or 4 ''to the hydraulic reservoir, on which a main piston 11 of a membrane cylinder 33 acts, which is actuated hydraulically, pneumatically or mechanically. The main piston 11 of the diaphragm cylinder 33 is surrounded by a return spring 18 .

The hydraulic lines 4 , 4 'and 4 ''can be shut off via individual check valves 6 .

In Fig. 1 a single clamping cylinder 2 is associated with a so-called. Booster pin 1, which has the task to increase the pressure on the associated clamping cylinder 2. As a result, the pin 22 of the printer is increasing pin 1 via an electromagnet 34 , which can be controlled by a (not shown) potentiometer into which the clamping cylinder 2 associated hydraulic reservoir is moved, whereby a high contact pressure of the associated holding member 7 on the workpiece 15 is generated.

Working principle: First, the workpiece 15 to be machined is placed in the clamping area or held therein. Subsequently, with the shut-off valves 6 open, the main piston 11 is moved over the diaphragm cylinder 33 , as a result of which the holding members 7 of the individual clamping cylinders 2 move up to the workpiece and fix it (prestress).

In this pretensioned state, the workpiece 15 can be adjusted or centered in a simple manner via a machine-side mandrel (not shown) which engages a bore 30 in the workpiece, since the clamping cylinders 2 are located in a self-contained hydraulic system.

As soon as the preloaded workpiece 15 has been centered, the check valves 6 are closed, as a result of which it is no longer possible to change the position of the preloaded workpiece. Then the pressure on the associated clamping cylinder 2 is increased and the workpiece 15 is clamped in the centered position via the pressure increasing pin 1 by switching on the potentiometer and moving the pin 22 into the hydraulic reservoir. The workpiece can then be machined. The diaphragm cylinder 33 has a return spring 18 , which is to ensure that when the diaphragm cylinder 33 is relieved, it returns to the starting position, so that when the check valves are open, the individual holding members 7 of the tensioning cylinder 2 also return to their starting position.

Fig. 2 shows a clamping cylinder 2 according to the invention, which can be used for rough and tight clamping of a workpiece ver. The cylinder chamber 17 is controlled by the working piston 2 'of the clamping cylinder 2 into two cylinder chambers 17' and 17 '' divided, wherein spaces in the two cylinders 17 ', 17' 'hydraulic fluid is provided. The two cylinder spaces 17 ', 17 ''are connected by a hydraulic or overflow line 4 , in which a check valve 6 is switched on. On the upper housing cover 9 there is a pressure-increasing pin 1 , which can be inserted into the cylinder chamber 17 at different depths, depending on a grid 3 .

At the upper cover 9 of the clamping cylinder 2 continues to be a pressure control piston see provided with display scale 5, wherein the pressure control piston 5 has for example a compression spring. 8 Furthermore, there is a compensating line 31 and a compensating tank 32 on the lower housing cover on the lower housing cover 10 .

To fix an object or workpiece, the working piston 2 'of the clamping cylinder 2 is, for example, manually moved until the holding member 7 on the workpiece (not shown in Fig. 2) workpiece. The check valve 6 is opened to ensure a compensating flow between the two ge separate cylinder spaces. Is the holding member 7 or the arranged on the top of the holding member 7 (not shown in Fig. 2) claw on the workpiece, is actuated, ie moving the pressure increase pin 1 in the cylinder space 17 ', the pressure in the latter. This causes an increase in the holding force exerted on the upper side of a workpiece via the clamping claw.

To ensure that höhungsstifts 1 hydraulic fluid in the lower portion of the cylinder chamber 17 upon actuation of the printer 'can escape, one from equal circuit 31 and a surge tank 32 pre see, space in which the hydraulic fluid from the cylinder 17' can escape.

From the top view of the clamping cylinder 2 shown in Fig. 2, the operation of the screening 3 is he recognizable. The head of the pressure increasing pin 1 has a recess 36 which ensures an axial displacement of the pin 22 along the grid 3 .

For coarse adjustment of the holding member 7 carried by the cylinder 2 ', a manually operable toggle lever 14 can be provided according to FIG. 3, which is provided with an adjusting screw 13 for adjusting the respective work area. The toggle lever 14 actuates a master cylinder 11 , the movement of which directly affects the movement of the piston 2 'of the clamping cylinder 2 . By actuating the toggle lever 14 , the workpiece is preloaded or the individual holding members are adapted to the contour of the workpiece. Final clamping of the workpiece is again ensured by actuation of the pressure increasing pin 1 , which is arranged axially adjustable in FIG. 3 via a thread 28 .

To limit the load, the clamping cylinder 2 in Fig. 3 has a pressure relief valve 6 , which opens when a certain pressure prevailing in the hydraulic reservoir is exceeded, the opening pressure being predetermined by a pressure spring 8 or can be varied via an adjusting screw 6 '. The housing of the clamping cylinder 2 corresponds to the clamping cylinder housing shown in Fig. 2.

Fig. 4 shows a further embodiment of the clamping cylinder 2 according to the invention, in which the working piston 16 is designed as a ring and loosely abuts the upper housing cover 9 . Provided within the housing 25 is a housing insert 10 which has an annular recess 27 into which the piston 16 engages, so that the housing insert 10 can be moved along the loose piston 16 within the housing 24 .

There are several arms 19 on the side of the housing insert 10 , of which only one is shown in FIG. 4 for the sake of clarity. Clamping elements, for example clamping claws, are fastened to the arms 19 . The respective arm 19 extends through an associated opening 25 , which is arranged laterally in the housing 24 . The arm 19 can therefore be moved up or down according to the length of the opening (see arrow A in FIG. 4).

The housing insert 10 is connected to a centrally arranged piston rod 23 . The piston rod 23 comprises two piston rod sections 23 'and 23 ''screwed together, which are screwed together to form a constriction. The inside of the Ge housing insert 10 is for receiving the two piston rod sections 23 'and 23 ''forms complementary. The arrangement causes that the housing insert 10 can be tilted relative to the piston rod 23 due to the interaction of the piston rod 23 to the housing insert 10 in a ge know area. The connection of the piston rod 23 to the housing insert 10 acts due to the rounded design of the constriction of the piston rod 23 or the complementarily shaped section of the housing insert 10 Ge as it were a ball joint. The provision of the housing insert 10 when the pressure is released is ensured by a return spring 18 .

By actuating the pump 14 connected to a hydraulic accumulator 20 , the housing insert 10 is pressed down, as a result of which the arm 19 , on which the tensioning element is arranged, also moves downward. This allows the workpiece to be preloaded. The valve 6 is then closed and the pressure increasing pin 1 is actuated to clamp the workpiece. The certain pivoting or tilting speed between the piston rod 23 and the housing insert 10 enables the clamping of workpieces with inclined plane surfaces.

When the clamping cylinder 2 is relieved, a compression spring 18 ensures that the housing insert moves upward, thereby releasing the workpiece.

FIG. 5 only shows, for the sake of clarity, how a workpiece 15 is clamped using the clamping cylinder 2 shown in FIG. 4. The arms 19 are each connected via links 35 to the clamping claws 26 , so that the workpiece 15 can be clamped on both sides and thus securely by actuating the clamping cylinder 2 . The workpiece ( 15 ) is advantageously clamped onto the upper side of the clamping cylinder 2 using the clamping claws 26 .

Reference symbol list

1 pressure increase pin
2 clamping cylinders
2 ′ working piston
3 grid
4 Overflow line / hydraulic line
4 ′ hydraulic line
4 ′ ′ hydraulic line
5 pressure regulating pistons with display scale
6 shut-off valve
6 ′ set screw
7 holding link
8 compression spring
9 Upper housing cover
10 Lower housing cover
11 main pistons
12 housings for work area pistons
13 Set screw for the work area
14 toggle lever, mechanical pump or pneumatic unit
15 workpiece
16 pistons
17 cylinder space
17 ′ upper cylinder space
17 '' lower cylinder space
18 return spring
19 arm
20 memories
21 locking arm for work area
22 Pressure increase pin
23 piston rod
23 ′ piston rod section
23 '' piston rod section
24 housing
25 Opening the housing
26 clamping claw
27 annular recess
28 threads
29 display scale
30 hole / workpiece
31 compensation line
32 expansion tank
33 membrane cylinders
34 electromagnet
35 link for connecting arm 19 and claw 26
36 recess

Claims (22)

1. Clamping device, in particular for milling or turning machines for clamping an irregularly shaped workpiece using a plurality of clamping cylinders, which keep this workpiece motionless during machining, characterized in that

• a) the clamping cylinders ( 2 ) are operated hydraulically and are arranged in such a way that they provide a receptacle or a chuck, as it were,
• b) all clamping cylinders ( 2 ) are connected to one and the same hydraulic reservoir,
• c) means are provided (14) which is capable centrally apply pressure to the hydraulic reservoir, whereby the retaining members (7) of each clamping cylinder (2) to the workpiece (15) moves toward and the workpiece (15) can be biased thereby,
• d) the location of the c preloaded workpiece ( 15 ) can be centered or adjusted by the machining unit, for example by means of a mandrel or the like,
• e) the connection of the individual clamping cylinders to the hydraulic reservoir is separable and
• f) at least one clamping cylinder ( 2 ) is equipped with a pressure increasing pin ( 1 ), by means of which an increase in pressure as a result of moving the pin ( 22 ) into the hydraulic reservoir of the respective clamping cylinder ( 2 ) can be achieved.

2. Clamping device according to claim 1, characterized in that the clamping cylinder ( 2 ) via in particular parallel lines ( 4 , 4 ', 4 '') with each other and with the device ( 14 ) for generating the pressure and the respective separation the clamping cylinder ( 2 ) through in the lines ( 4 , 4 ', 4 '') arranged valves ( 6 ), preferably check valves, takes place. 3. Clamping device according to claim 2, characterized in that preferably adjustable pressure valves are provided as valves ( 6 ). 4. Clamping device according to claims 1-3, characterized in that the pin ( 22 ) of the pressure increasing pin ( 1 ) has a small diameter compared to the diameter of the piston of the clamping cylinder ( 2 ). 5. Clamping device according to claim 4, characterized in that the pressure increasing pin ( 1 ) can be actuated manually, preferably via a thread or a raster or the like. 6. Clamping device according to claims 1-4, characterized in that the pressure increasing pin ( 1 ) electro magnetically, preferably via an electric magnet ( 3 ) and a potentiometer ( 5 ) movable bar and thereby the pressure is adjustable. 7. Clamping device according to claims 1-6, characterized in that as a device ( 14 ) for increasing the pressure or for moving the holding members ( 7 ), a mechanical toggle lever, a hydraulic pump or a pneumatic system, which (s) each on a main piston ( 11 ) acts, is provided. 8. Clamping device according to claim 7, characterized in that a return spring ( 18 ) is provided, which retracts the main piston ( 11 ) when the hydraulic or mechanical or pneumatic pressure is released, as a result of which the holding members ( 7 ) also withdraw and the workpiece ( 15 ) release. 9. Clamping device according to claims 1-8, characterized in that the clamping cylinders ( 2 ) are arranged in a circular or semi-spherical, as it were, grape-shaped around the work piece ( 15 ). 10. Clamping device according to claims 1-9, characterized in that a plurality of preferably grid-like ver divided clamping cylinders of small dimensions are easily seen, which attack the workpiece ( 15 ) at points. 11. Clamping cylinder in particular for use in a clamping device according to claims 1-10, characterized in that the clamping cylinder ( 2 ) has a cylinder space ( 17 ) with a piston ( 2 ') arranged displaceably therein, with on both sides of the piston ( 2nd ') The cylinder is filled with hydraulic fluid speed, both sides of the cylinder chamber ( 17 ) separated by the piston ( 2 ') via a valve ( 6 ), in particular a check valve equipped with a compensating line ( 4 ), and one another in the cylinder space ( 17 ) movable printer heightening pin ( 1 ) for pressure fine tuning is seen. 12. Clamping cylinder according to claim 11, characterized in that the pressure-increasing pin ( 1 ) can preferably be actuated manually via a thread ( 28 ) or a grid ( 3 ). 13. Clamping cylinder according to claim 11 or 12, characterized in that the clamping cylinder ( 2 ) has a particularly spring-loaded pressure regulating piston ( 5 ) with a display scale ( 29 ). 14. Clamping cylinder according to claims 11-13, characterized in that the clamping cylinder ( 2 ) with a mechanically in particular mechanically via a toggle lever ( 14 ) driven main piston ( 11 ) is in hydraulic connection, the actuation of a rough movement of the holding part ( 7th ) guaranteed. 15. Clamping cylinder according to claims 12-14, characterized in that a controllable pressure relief valve ( 5 ) is arranged in the compensating line ( 4 ) instead of the check valve ( 6 ). 16, the clamping cylinder, characterized by a housing (24), a ring- or disc-like housing insert (10) which is arranged along a arranged in the housing (24) piston (16) axially movable in the housing (24) and at least two laterally through openings ( 25 ) of the housing ( 24 ) it has extending arms ( 19 ), on which clamping elements, for example clamping claws ( 26 ) are arranged and the movement of the housing insert ( 10 ) hydraulically via a cylinder space ( 17 ) between pistons ( 16 ) and housing insert ( 10 ). 17. Clamping device according to claim 16, characterized in that the housing insert ( 10 ) has an annular recess ( 27 ) on the end face, and the piston ( 16 ) is designed as a complementary ring and engages in the recess, with the piston ( 16 ) and recess ( 27 ) of the hydraulic fluid-filled cylinder space ( 17 ). 18. A clamping cylinder according to claim 16 or 17, characterized in that an axially movable through the housing (24) piston rod (23) is provided which is ge is articulated manner connected with the housing insert (10), whereby a pivoting of the housing insert (10) to piston rod ( 23 ) is made possible. 19. Clamping cylinder according to claims 16-18, characterized in that the connection of the clamping cylinder ( 1 ) for the device for generating ( 14 ) the hydraulic pressure via a check valve ( 6 ) is separable and for increasing the pressure or for clamping the work piece ( 15 ) a pressure increase pin ( 1 ) is provided. 20. Tensioning cylinder according to claim 19, characterized in that the pressure increasing pin ( 1 ) can be actuated manually, preferably via a thread ( 28 ) or a grid ( 3 ). 21. Clamping cylinder according to claim 19 or 20, characterized in that a pressure regulating piston ( 5 ) with a display scale ( 29 ) is provided on the clamping cylinder ( 2 ) or on the pressure-increasing pin ( 1 ). 22. A method for clamping a workpiece in particular using a Einspannvor direction according to claims 1-10, characterized by the following process steps:

• a) inserting the workpiece ( 15 ) and increasing the hydraulic pressure until the holding members ( 7 ) engage the workpiece ( 15 ) completely and hold it with pre-tension,
• b) Centering or aligning the a preloaded workpiece ( 15 ) in particular by a machine-side part, for example by a centering mandrel,
• c) closing the individual clamping cylinders ( 1 ) with the hydraulic reservoir connecting valves ( 6 ), and
• d) subsequent actuation of the pressure increase pin ( 1 ), whereby the workpiece ( 15 ) is clamped.