JPH02262967A - Chuck device for workpiece - Google Patents

Abstract

PURPOSE: To transmit a uniform holding force to a workpiece through jaws by providing a fixing device for tightening the jaws after forming the jaw as a two-arm lever and holding the workpiece to a jaw holder by a second bracket. CONSTITUTION: Jaw holders 2 and 3 are provided with chambers 29, 41, and 42 open toward guide surfaces 33 and 40 of a guide device 1 capable of being connected to a compressed air source so as to move the jaw holders 2 and 3 with as less friction as possible, and an air cushion is formed between the guide surfaces of the chambers 29, 41, and 42 and the guide surfaces of the guide device 1. In addition, a cylinder, a piston, and units 11 and 12 which move two jaw holders 2 and 3 closely to each other and away from each other are arranged at the height of a workpiece receiving center, jaws 4 and 5 are formed as a two-arm lever, holding portions 8 and 9 are provided at the free end part of a first bracket, and the workipiece is held to the jaw holders 2 and 3 by second brackets 60 and 61. Then the jaws are tightened by the fixing devices 56 and 57.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a chuck device for workpieces.

PRIOR TECHNOLOGY In the case of a known chuck device of this type (hico + CoKG brochure ``Central Vise''), the jaw holder is installed on a machine tool by moving it over the edge of the guide frame by means of a member that guides the floor. A cylinder-piston unit that is guided and used to push the respective jaw holder grips the jaw holder directly above the guide device.

Moreover, the jaws are rotatably mounted as circular discs in the jaw holder, and up to the hollowed out part,
It has a slit sufficient to receive the workpiece.

Problems to be Solved by the Invention Due to this configuration, especially when the chuck device needs to suspend the workpiece in a movable manner,
A number of serious shortcomings have been revealed that demand attention. The reasons for these are diverse. One reason is that the force of the cylinder-piston unit to move the jaw retainer acts at a large distance to the center of the workpiece, so when the jaws are placed in contact with the workpiece, the maximum torque is occurs, in that this results in tightening of the jaw retainer in the direction opposite to the guiding direction. According to this, it is not guaranteed that the workpiece will actually be centered, since the jaw holders facing each other can tilt at various times. This effect is confirmed by the fact that the guide of the jaw holder imposes a certain friction value which does not necessarily result in equal results in both jaw holders, which is already centered at its ends along the reference plane. This facilitates the above-mentioned tilting process in which the workpiece is forced out of the central portion.

Another disadvantage is that the jaws consisting of circular discs are provided on their circumferential surface in the jaw holder, and when a workpiece is gripped, the jaws receive the workpiece through the gripping process. Because of the arrangement of the slits, the circumferential surface of the jaws and the corresponding bearing surface of the jaw holder act as clamping surfaces since they are extended to the hollowed out portion. In this case the jaws can be tightened at different times.

It is not always possible to center the processed product.

It is an object of the present invention to create a chuck device of this type in such a way that a uniform gripping force is applied through the jaws to the workpiece.

Means to solve problems This object is solved by a method according to claim 1.

By arranging a chamber that can be freely connected to a compressed air source and has an opening toward the guide surface, it is possible to create air action between the guide surface of the jaw retainer and the guide surface of the guide device. , the jaw retainer will float on this air action. Friction between the jaw holder and the guide device can thus be avoided, especially if air tension is created over the entire guide surface. Different friction values when moving the mutually movable jaw holders are therefore also excluded. Other ways to avoid the risk of tipping during gripping are to
The method consists in applying a force to the cylinder-piston unit during the gripping process at or near the workpiece, and by using this method, when the jaw is placed in contact with the workpiece, the maximum force generated due to the eccentric action of one gripping force is Torque can be avoided. Any eccentric action of the gripping force takes place in conjunction with the frictional forces that may be present between the jaw holder and the guide device, which are considered to be slight, unless the entire guide surface is acted upon by means of an air action. The eccentric force action is selected in this case in such a way that the maximum torque specified on the basis of the friction coefficient exactly cancels out. By constructing the jaws as two-armed levers and by arranging the two-armed levers around a pivot axis, the jaws provide a low-friction, inclusive adjustment method with respect to the workpiece, as is known in the art. As in the case of , a much more convenient method is provided when compared to the case where it is provided on its circumferential surface. By means of a locking device that engages in the second arm of the two-armed jaw and tightens the jaw, which is adjusted according to the action of the gripping force, this jaw is centered during the process of being movably suspended. Fixation of the jaws is achieved only when the jaws are aligned with the workpiece held in place.

It is clear that all of these measures lead to reaction forces of practically equal magnitude during the gripping process, so that when movably suspended, the workpiece, which is already kept centered, In the case of a central chuck that can remain in that position and whose jaws are immovably fixed from the beginning and centered with respect to the axis of the machine, the centering position of the workpiece has been precisely achieved. .

In order to make sure that no movement is possible on the guide device after the end of the gripping process of the jaw retainer, which may occur, for example, during pressure fluctuations in the hydraulic circuit or when this breaks down, the present invention is useful. According to another advantageous embodiment, the clamping device for each jaw retainer includes a cylinder-piston unit, the piston of which has a beveled control part, which When used, the shim is movable and, in the displaced state, is pressed towards the jaw retainer, and the piston can be moved into the fixed position by the force of the spring and into the released position by the pressurized medium of the hydraulic circuit. It becomes. The jaw retainer is thus tightened towards its guide device, while in order to release the tightening device the piston is moved by the pressurized medium against the action of the spring.

An advantageous refinement of the invention is that the locking device has a hydraulic system in which the piston acts laterally towards the second arm of the jaw and is connected to the same hydraulic circuit to which the tightening device is also connected. It becomes clear that a cylinder-piston unit is provided for tightening the jaws. In this way, the securing of the jaws to the jaw holder and the securing of the jaw holder to the guide device is achieved simultaneously. Therefore, any movement due to the gripping forces of the jaw retainer and the jaws acting to push each other will not occur. In a further embodiment of the invention, a blocking device for the jaws is provided so that, due to the central chuck, the jaws are precisely fixed from the front in the jaw holder and are also centered and aligned on the axis of the machine. Provided in each jaw retainer, this blocking device blocks the jaws for the central chuck in an aligned position relative to the axis of the machine and, when unblocked, moves Allows free movement of the jaws for the chuck to be suspended.

In another advantageous embodiment of the invention, the synchronizing device includes a pull rod, which is formed with a rack within the jaw retainer and is rotatably mounted on a gear wheel. Cooperatively, this gear meshes with a rack arranged adjacent to the jaw, and this tension bar is connected via a releasable coupling device within the confines of the other opposing jaw retainer. It is tied to this so that it can be released.

Synchronizers with racks, guide pinions and other racks adjoining the jaw holders are used in the gripping device described and known at the outset, if the gripping device is switched into a movable suspended state. , that's where the problem arises.

In addition to this, the engagement between the rack and the pinion is released, so that the connection of the one-way jaw retainer is interrupted via the rack. This is essential for movably suspended chucks, but in order to ensure accurate centering of the jaws on the axis of the machine, when switching to self-centering, the meshing of the same teeth must again be precisely Problems arise in deriving this.

This is because in the case of other tooth engagements, this centering orientation is not carried out due to manufacturing tolerances. allows a changeover from a movable suspended chuck to a centered chuck without considerable expense, as well as this changeover in the opposite direction, i.e. without compromising the -based centering of the jaw mechanics. This is solved by what can be done.

Due to the releasable connection, the tooth engagement between the rack and the pinion does not need to be released, so that it is possible to switch from one mode of operation to another, i.e. from centering to movably suspended chucks, and so on. Switching in the opposite direction can be carried out smoothly and the above-mentioned mismeshing of the teeth, which is manifested due to the different meshing positions, is avoided.

A particularly simple form of the coupler for releasing the synchronizer is such that it has a transmission body which is firmly set on the tension rod, as well as a coupling part which is set in the assigned jaw retainer part, and which the part is guided between end positions transversely to the direction of movement of the jaw retainer;
In the -end position, there is an interlock between itself and the transmission body, and in the other end position, a relative movement is possible between itself and the transmission body. Since the connecting part is held tightly and without gaps in the direction of movement of the jaws, a precise movement with the gear of the jaw retainer assigned to this connecting part is achieved, so that both jaw retainers , each operates synchronously in opposite directions.

A particularly simple form of the coupler according to the invention is advantageously constructed in a U-shape with arms whose connecting parts extend at a distance from each other in the direction of their free ends, and between these arms. This is achieved by the fact that the transmission bodies are housed in the arms, the small distance between the arms corresponding to the size of the transmission bodies, and that the connecting parts are movable in the direction of the arms. Interlocking is established in that when the connecting part is moved in one direction, the transmission body is moved towards the transmission body until it comes into exact contact with both arms. When this connecting part is moved in the other direction, various movements of the jaw retainer are possible due to the chuck movably suspended between the transmission body and the extended arm of the connecting part. There will be enough space to allow the

A design-simple solution is provided according to the invention in that the jaw holder chamber is connected to a lubricating oil supply. In addition to the formation of an air traction, this also ensures the lubricity of the mutually sliding surfaces. This lubricating oil is essential since no air action is required during the entire movement process of the jaw retainer.

This air action, in the case of this type of guide device,
The normal gap size is sufficient to serve to separate the jaw retainer from its guide frame edges, while at the same time allowing comprehensive frictionless movement of the jaw retainer.

In a further embodiment of the invention, the surface of the jaw holder, which does not have a chamber for supplying compressed air, which cooperates with the guide surface of the guide device has guide rollers.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention will be explained in more detail below with reference to the drawings, which are schematically illustrated embodiments.

Two jaw holders 2, 3 are movably arranged on the guide device 1, each of which contains a jaw 4.5, which jaws are each horizontally oriented, i.e. relative to the guide device 1. It is mounted on the jaw retainer 2.3 so as to be pivotable about laterally extending axes 6, 7. each jaw 4
5 has a gripping part 8.9 for receiving the workpiece lO to be gripped.

The jaw retainer 2.3 is movable by means of a cylinder-piston unit 11.12. Furthermore, the piston is designed as a double-acting piston and can be influenced in the desired direction of movement from one side or the other by the pressure medium of the hydraulic circuit. Jaw retainer is processed product 1
When moved to grip 0, they are tightened by the guide device 1 while in the gripping position. For this, cylinder-piston units 15.16 or 17, 18
have each. Tightening devices 13,14 integrated into each jaw retainer are used, these tightening devices are connected to the road line 19.
．． Cylinder-piston unit 11.1 via 20
2 and connected to the same hydraulic circuit that serves to move the jaw retainer.

Although the pistons 16, 18 are each influenced only from one side by the hydraulic circuit, they are subjected to the spring action of the spring device 21, 22 from the other side.

Each piston is provided with an actuating part 23.24 which is provided with a beveled surface 25.26 on its upper side. piston·
The cylinder units 15.16.17.18 are placed in the guide device. Each slope 25,26 has a cylinder 15
In 17 to 17 there are clamping parts 27.28 guided transversely to the sliding direction of the piston 23.24, which clamping parts 25.26 are guided along the slope 25.26 as the piston moves.
is pressed towards or released from the upper jaw retainer. These slopes are designed in such a way that each clamping part 27, 28 is pressed towards the jaw holder by means of the spring device 21, 22 under the load of the piston 23, 24, so that this jaw holder It is tightened towards the guide device 1. To release the jaw retainer, the piston 16.18 is subjected to a pressure medium. Tightening by a spring device and releasing by means of a pressure medium has the advantage that the tightening action is always constant and does not exhibit any fluctuations as occur in hydraulic circuits.

Since the same hydraulic circuit is utilized for the movement of the jaw holder and for the tightening of this jaw holder, it is possible to simultaneously ensure the release of the tightening device when introducing the movement process.

In order to be able to move the two jaw retainers 2.3 as frictionlessly as possible, they are provided with guide surfaces 31.
A chamber 41 , 42 with 32 is provided, these guide surfaces cooperating with a guide surface 33 on the guide device 1 . These chambers open downwards, ie in the direction of the guide surface 33 of the guide device 1, and can be connected via conductors 34, 35 to a source of compressed air. For this purpose, between the guide surfaces 31, 32 of the jaw retainers 2, 3 and the guide surface 33 of the guide device 1,
Since an air action can be created to gently lift each jaw holder 2, 3 from the guide surface 33, the jaw holder can be moved with as little friction as possible.

The jaw retainer 2.3 is provided with a lower gripping frame edge 36.37 having guide surfaces 38.39, which cooperate with corresponding guide surfaces 40 of the guide device 1. do. Air traction can also be formed on these guide surfaces to reduce friction. In the jaw holder 2, as can be seen in the drawing, the lower gripping frame edge 36 has an upwardly open chamber 29, which chamber is connected via a line 30 to a source of compressed air. Since the chamber 29 is open to the guide surface 40 of the guide device 1, the guide surface 40.39
An air action can be formed between the two.

As a variation of this, in the case of the jaw retainer 3, the guide device 1
A guide roller 43 cooperating with a guide surface 40 is arranged in the lower gripping frame edge 37. These guide rollers are
In the case of the jaw retainer 2, this reduces friction, similar to that achieved by the chamber 29.

Due to this characteristic which allows the jaw holder 2.3 to be moved on the guide device 1 with the lowest possible friction, the maximum torque about the transverse axis of the jaw holder is particularly eliminated. Cylinder piston unit 1
1.12 must be placed slightly below the axis 44 of the machine in order to move the jaw retainer. Therefore, when the jaws are placed against a part of the workpiece, a maximum torque occurs despite the eccentricity of the extension force. This is because the force acts only slightly outside this central part. The outward movement of the central part is necessary in order to offset the existing frictional forces, although various measures have been taken.

In FIG. 1, a chuck device for central gripping is shown. To advance the gripping process, jaws 4,
5 is a wedge-shaped block 45.5 in the jaw retainers 2,3.
It is secured in alignment with the shaft 44 of the mechanical device using a block device designed as 46 . The wedge-shaped blocks 45, 46 prevent a pivoting movement of the jaws about the axes 6, 7.

In order to achieve the precise synchronization of both jaw holders, which is essential for central gripping, both jaw holders are connected to each other via a synchronizer 47. This synchronizing device has a rack 49 arranged in the area of the jaw holder 2 and a pull rod 48 cooperating with a gear wheel 50 arranged rotatably along the guide device 1. The gear is mounted on a rack 5 provided on the jaw retainer 2.
It meshes with 1. Thus, when the pull bar 48 moves to the left in the drawing, the jaw retainer 2 is moved to the right. In the area of the other jaw retainer 3 , a transmission body 52 is firmly mounted on the tension rod 48 , cooperating with a U-shaped coupling part 53 , which U-shaped coupling part of the jaw retainer 3 . It is moved in a direction perpendicular to the direction of movement.

The connecting part 53 is provided with armrests 54,55 which are spaced apart at each end of the connecting part. Due to the position of the coupling part 53 shown in FIG.
Despite various forces caused due to friction or irregular action of the piston unit 11.12, it will always be reciprocated an equal distance towards the axis 44 of the mechanical device.

FIG. 2 shows a movably suspended gripping device for a chuck. In order to movably suspend a chuck that holds the workpiece centered along a reference plane by another chuck device, the chuck shown here extends along an outer surface that is not centered relative to the reference plane. When the workpiece is gripped by the chuck fixture, the jaws must compensate for this eccentric movement so that the tension on the already centered workpiece remains unchanged. In order to provide this possibility of cancellation, which must be possible, first the blocking devices 45, 46 are released. This allows the jaws 4.5 to be pivoted about their axes 6, 7 and adapted to the height at which the workpiece is installed. To move eccentrically in the horizontal direction,
The jaws must be able to compensate for this movement determined on the basis of the already grasped reference surface.

In this regard, the connection formed by transmission body 52 and coupling part 53 is released in order to forcefully abort the synchronization. In order to release this connection, the connecting part 53 is moved upwards, so that play is created between the connecting part 53 and the transmission body 52 because the arms 54 and 55 are separated. This game is.

movably suspended chuck or jaws 4.5
is sufficient to enable gripping by the jaws, so that the jaws can be of varying spacing relative to the axis 44 of the mechanical device.

If the chuck fixture is provided for a movably suspended chuck as just described, with the wedge-shaped block 45, 46 and the connecting piece 53 being movable by hand, the jaws The holders 2, 3 are made movable towards the centered workpiece using the cylinder-piston unit 11.12 until the jaws 4.5 chuck the workpiece. Because the synchronization is discontinued and the jaws 4.5 are pivotable, it is possible to grip workpieces that are held with their outer diameter offset relative to the axis 44 of the machine. In order to maintain this state here, the jaws 4.5 must be fixed in their position thus achieved; for this purpose a fixing device 56 consisting of a cylinder-piston unit is used.
, 57 are used for each jaw retainer, and this cylinder-piston unit is connected to the same hydraulic circuit that serves to control the tightening devices 13, 14. In the case of this fixing device, a piston 58.degree. 59 is loaded by the spring arrangement so that the piston pushes on the arm 60.61 which is firmly connected to the jaw 4.5 on the basis of the force of the spring, so that the jaw will be fixed in its adjusted position. .

To release this locking device, the respective cylinder-piston unit 56, 57 is influenced by a pressure medium.

In other words, the prearranged hydraulic circuit acts to displace the jaw retainer and at the same time tightens the clamping device 13.14.
and the fixing devices 56,57 are released.

[Brief explanation of drawings]

1 is a front view of an embodiment of the invention in an operating position adjusted for central gripping; FIG. 2 is a front view of an embodiment of the invention in an operating position adjusted for a movably suspended chuck; FIG. The front view, Figure 3 is the same as the above plan view, Figure 4.
The figure is a sectional view taken along the line IV-IV in FIG. 1. 2.3... Jaw retainer 8.9... Clamping portion 11.12... Cylinder piston unit 21.
22...Spring device 25, 26...Slope 29...Room 41.42...Room 45, 46...Wedge-shaped block 48...Tension rod 51...Rack 53... ...Connecting parts 56, 57...Fixing device 60.61...Arm Tree 1...Guiding device 4.5...Jaw lO...Processed product 13.14...Tightening device 23, 24... Operating parts 27, 28... Tightening parts 33, 38, 39, 40... Guide surface 43... Guide roller 47... Synchronizer 50... Gear 52... Transmission Body 54, 55... Arm Tree 58, 59... Piston

Claims (1)

[Claims] 1. The cylinder-piston units are movably arranged on a guide device and can be tightened via a tightening device, and are moved relative to each other using cylinder-piston units connected to the same hydraulic circuit. At the outer circumference of the workpiece, which has a two-jaw retainer and which is held centered using a separate chuck fitting, on the basis of rotationally symmetrical gripping surfaces, holes or outer surfaces. In chuck devices for centering chucks and for movably suspended chucks, these jaw retainers are centered on an axis extending transversely to the slider direction of the jaw retainers in order to accommodate the workpiece. A freely movable jaw with a cutout is provided for receiving the workpiece, which jaw is moved towards the jaw holder when the gripping force exerted by moving the jaw holder is exerted. Both jaw retainers are connected via a releasable synchronizer, which in its active position is required to center the chuck on the axis of its mechanical device. Enables accurate synchronization,
Also in the released position, the movably suspended chuck allows various movements of these jaw holders, and at each jaw holder (2) (3) it is possible to connect to a source of compressed air. The surface (33) of the guiding device (1) that is
Rooms (29) (41) (4) open towards (40)
2), and the guide surface (33) (4) of this guide device (1)
0) co-operating with at least one of the guide surfaces (38) (39);
A surface is provided, each cylinder piston unit (11) (12) at the height of said workpiece receiving center and a jaw retainer (2) (3).
The guide device (1) of each jaw (
4) (5) is designed as a two-armed lever, by means of which said first arm holds the clamping parts (8) and (9) at its free end part of the workpiece (10). The second arms (60, 61) securely grip the workpiece toward the jaw retainers (2, 3), and then use the fixing devices (56, 57). A chuck device characterized in that it can be tightened. 2. The tightening device (13) (14) is connected to the cylinder-piston unit (15) (16) (1) for each jaw retainer.
7) (18) is built-in, and the cylinder, piston,
The piston of the unit is provided with actuating parts (23) and (24) with slopes (25) and (26), and the control parts make the clamping parts (27) and (28) movable. With the attached parts moved, attach the jaw retainer (2) (
3) and the pistons (16) (18
) is movable into the clamping position by the force of the spring devices (21, 22) and into the releasing position by the pressurized medium of the hydraulic circuit. Device. 3. The fixing device (56) (57) has a hydraulically actuated cylinder-piston unit for tightening the jaws, and the piston (58) (59) of the unit
are the second arms (60) (61) of the jaws (4) (5).
The tightening device (13) (14)
The chuck device according to claim 1 or 2, wherein the chuck device is connected to the same hydraulic circuit as that to which the chuck device is connected. 4. Each jaw retainer (2) (3) has jaws (4) (5).
) are provided with blocking devices (45) (46);
The blocking device is movably suspended for fixing the jaws in an aligned position relative to the axis (44) of the mechanical device for centering the chuck and for free movement of the jaws after release. A chuck device according to any one of claims 1 to 3, characterized in that it is capable of being used for a chuck that is 5. The synchronizer (47) has a drawbar (48), which in the area of one jaw holder (2) is fitted with a rack (
49) is formed and cooperates with a rotatably mounted gearwheel (50) which meshes with a rack (51) arranged on the jaw retainer (2) and which allows the drawbar ( 48) is another jaw retainer (3) on the opposite side
2. The chuck device according to claim 1, wherein the chuck device is releasably connected to the jaw retainer via a coupler within a range of . 6. The coupler is a transmission body (52) immovably placed on the pull rod (48) in order to release the synchronizer (47)
, and in said assigned part of the jaw holder (3) has a connecting part (53) placed in contact with said jaw holder, said connecting part preventing the sliding of the jaw holder (3). guided between two end positions transversely, one end position allowing interlocking of the jaw retainer and the transmission body (52), and the other end position allowing the jaw retainer and the transmission body (52) to interlock. The chuck device according to claim 5, characterized in that it is adapted to allow relative movement with the body (52). 7. The connecting part (53) has arms (54) (55) which are extended apart from each other in the direction of both free ends of the connecting part.
), and the arm accommodates a transmission body (52) between the two arms, the smallest distance between the arms (54, 55) being equal to the transmission body ( 52
), and the connecting part (53) corresponds to the size of the arm (
7. The chuck device according to claim 6, wherein the chuck device is movable in the directions of (54) and (55). 8. Jaw retainer (2) (3) chamber (29) (41)
The chuck device according to any one of claims 1 to 7, characterized in that (42) is connected to a source of a lubricating oil supply device. 9. Jaw retainer (3) without said chamber for compressed air supply cooperating with the guide surface (40) of the guide device (1);
9. The chuck device according to claim 1, wherein the surfaces (38) and (39) are provided with guide rollers (43).