Technical field:

The present invention relates to a method for machining workpieces or to hold workpieces for machining in a holding arrangement comprising two or more holding elements arranged to a foundation.

Background:

There is a need for a new method for machining workpieces in machines. This need has been accentuated as the machines often used today are extensive in construction and are expensive. Further, the high unit time costs and the often long series of the same machining have also an influ¬ ence. The long series of machining means that the same working operation being carried out in several separate workpieces. Numerically controlled machines and similar are examples of such machines, the costs of which are high, and where effective time factors are required. Besides, there is also a need not to proceed with an error or in addition to increase an error made in operation. Further, machine setting facilities should be more efficiently used.

Technical problems: In known methods, the machine work cycle must be repeated for each part or workpiece to be machined. If several workpieces are to be machined with the same setting and the same cycle, and even if only a minor fault exists in the setting or in the workpiece, in the case for example of a workpiece that has been cut slightly wrong, then this fault will be transferred to the entire work line and to each individual workpiece, i.e. the operation will be executed at the wrong place on the workpiece and moreover this fault will be doubled at each following workpiece or operation. Such repetitive work cycles may perhaps be used at present for small parts in numerically controlled machines but in this case the workpieces are not arranged one after the other.

Solution:

The utilisation of a method in accordance with the present invention ful¬ fils, however, the requirements made, while at the same time the inconven- iences of known methods are eliminated. Thus, an arrangement in accordance

with the invention is used which fulfils the requirements made and above all suppresses the nuisances caused by the known arrangements but the essentials are that a method in accordance with the invention owing to this on the whole is practicable. Thus, the method is time saving, partic- ularly when used in connection with NC machines and the like where a work cycle is to be repeated for several operations, whereby parts of the wor cycle can be used during machining of several workpieces. This is common in manual machines but greater advantages are provided with NC machines and similar numerically controlled machines, where the insertion or change of workpieces does not require to be carried out after each operation with the entire work cycle but the operation can be carried out in several work- pieces without repeated settings. The tool can move to a sensor point in the direction of work, or to the workpiece, and be applied to the machine in a position where the tool or the machine senses the position and on the basis of this fresh sensing execute its operation, whereby the operation is always carried out at the correct point on the workpiece, since the tool receives this positioning before each operation or machining of a workpiece. The method in accordance with the invention is thus character¬ ized in that, machining of a first workpiece arranged in the arrangement is repeated during machining of a second workpiece arranged in the arrange¬ ment, and so on, until all workpieces arranged in the arrangement have been machined in the intended manner. The invention thus comprises in addition an arrangement which has the design and characteristics indicated in the claims.

The arrangement can also be summarized as a vice or a multi vice primarily intended for NC, CNC and other similar machines, whereby several parts or workpieces can be clamped at the same time in the arrangement with an exact zero point for each and every one of the parts or the work pieces.

The arrangement also comprises at least two holding elements or vices, as the holding devices for a workpiece are placed at opposite sides on each holder element or vice. Thus, at least two vices must be utilized for clamping or anchoring of a workpiece and for the execution of the method. For this workpiece is utilized a first holding device on one of the hold¬ ing elements and a second holding device on a second holding element, the first holding device of which is utilized for a second workpiece which is clamped between the second holding element and a third holding element.

Thus, for two workpieces arranged one after the other three holding ele¬ ments are required, for four, five holding elements, etc. The row of arranged workpieces is thus concluded with a holding element, the one or first holding device of which is not utilized, or respectively, the second holding device of which is not utilized. Alternatively, it is also possible to use separate end holding elements which do not have unnecessary holding devices or the holding device which cannot be utilized, i.e. which is turned from the row of workpieces or holding elements.

Brief description of the drawings:

Further characteristics of and advantages with the method and the arrange¬ ment will in the following description of the invention be apparent by an embodiment, whereby a simultaneous reference will be made to the accompany¬ ing drawings, of which Fig. 1 shows from one side a part of an arrangement according to one embodiment, and shows two holding elements, whereby one of these is shown in section, Fig. 2 shows from above a part of the arrangement in Fig. 1, and Fig. 3 shows a vertical section of a part of the arrangement and a part of the arrangement from a second side.

Best mode for carrying out the invention:

Reference designation 1 in the figures shows a holding arrangement accord¬ ing to an embodiment and in the shape of a multi vice which comprises at least two or preferably several holding elements 2 which are arranged to be able to be arranged to a foundation 3. For this reason the holding elements 2 show first connecting elements 14 and the foundation 3 second connecting elements 15. According to the embodiment the first connecting elements 14 are formed as one or several cogs 4 arranged to one or more bodies, and the second connecting elements 15 are formed as rack gearings 35 with cogs 5, the rack gearings are arranged in parallel and at a dist- ance to each other, whereby the tooth pitch 24 or T according to one embodiment is 4,72 mm. The holding elements 2 can thus with their first connecting elements 14 be placed in engagement with and along the found¬ ation 3 or the second connecting device 15, 35 and it is possible for them to be anchored in the foundation 3 by fastening devices 31. According to the embodiment the fastening devices 31 are formed as bolts 32, screws or the like which reaches through the holding elements 2 and which are easily accessible from the top 12 of the holding elements 2 and which with a thread reaches into longitudinal grooves 34 or T-sectioned grooves shown

by the foundation 3. In said grooves are anchoring elements 33 arranged and in which the bolts 32 shall be brought into engagement.

The holding elements 2 show a first holding device 7 in the shape of a displaceable or retractable jaw with a gripping face 17, and a second holding device 9 in the shape of a fixed jaw or similar with a gripping face 19. The respective gripping faces 17 and 19 of the holding devices 7 and 9 are arranged on opposite sides 6 and 8 on the holding elements 2. The gripping faces are thus active in opposite directions when holding workpieces 10 and are in contact with the workpieces 10 in the holding position, i.e. that both the holding devices 7 and 9 are arranged to hold their own workpiece 10.

The flexible jaw 7 is arranged displaceable by means of control devices 28 and 29, for example in the shape of a wheel, which is rotatable on a threaded tap 29, journal or the like which is anchored in the flexible jaw 7 so that rotation of the wheel brings the jaw to displacement. This dis¬ placement, which is used to clamp the workpiece 10 in the intermediate space 20 between two adjacent holding elements 2, is only necessary for a short range. One of the jaws 7 in Fig. 1 is shown with reference designat¬ ion 7' in a protruded or fully protruded portion, whereby this displace¬ ment is T + 2 mm according to the embodiment shown of the arrangement 1. This displacement of the flexible jaw 7 can thus be used within this same area to clamp a workpiece but also to avoid defective dimensioning and the like of the workpiece, etc., such as for example in the case where the workpiece has been incorrectly cut.

Machining of workpieces 10 with small thickness, or of greater dimensions, or for workpieces or such said workpieces where a machining through the workpiece is to be carried out, such as one or several through holes in the workpiece, such workpieces can be arranged between holding faces 21 and 23 existing in a specially arranged or shaped third holding device 11, one of the faces is arranged on a special jaw, and the other is located on a designed part 25 on the fixed jaw 9. This designed part is arranged to extend on a level with the top side 12 of the holding element 2 or a supporting face on the top side 12 of the holding element 2 and with a part protruding above the said top side 12 or supporting face of the hold¬ ing element 2 and thus forming the holding face. The holding elements 2

may also be arranged with arrangeable or retractable fourth holding devices 13, or keys, on which a workpiece 10 may be supported for clamping between the holding elements 2 by utilization of the flexible or first jaw 7. In such a clamping of a workpiece it is possible to carry out a machin- ing passing through the workpiece, such as one or several through holes in the workpiece. The third holding device 11 may be shaped with a supporting face 27 which is preferably arranged on a level with the said top side 12 of the holding element 2 or possibly supporting face, whereby the said part 25 on the fixed jaw 9 is arranged on a corresponding level in the holding element or slightly above the said top side 12 of the holding element 2, whereby the said part 25 on the fixed jaw 9 is arranged on a corresponding level in the holding element.

For clamping of rod shaped workpieces 10, cylinders or similar, the fixed jaw can be provided with a horizontal running recess 16 or slot, see Fig. 1, or a vertical running slot 26, see Fig. 2. For clamping of workpieces 10 with small thickness and which does not show right angled edges, such as rounds or other objects with curved limiting edges, then the said third holding device 11 will be shaped turnable for connection to limiting edges of such a workpiece 10.

The said third holding device 11 is shaped in the form of several rods 18, holding pins or the like, arranged in each holding element 2, whereby the holding element shows a corresponding number of openings 36 or holes. The rods 18 are according to an example of the embodiment shaped freely turn- able round their axis and connect at their one end, for example, to the body for the first connecting element 14 and are also arranged displaceable in the openings 36 in the direction of said side 6 of the holding element 2. The displacement is regulated with the control devices 28, 29. When clamping such a said workpiece and during the clamping operat¬ ion, the third holding device 11 will adjust to the shape of the workpiece so that the connecting faces or the holding faces 21 of the rods 18 connect to the workpiece. Arrow 22 shows the possibilities of the rotatory move- movements for the rods 18.

Between the flexible jaw 7 or that part of the holding element 2, which the flexible jaw is arranged to, and the first connecting element, it is possible for a rubber packing 37 or other shock absorbing device, to be

arranged. The flexible jaw 7 does not extend according to the embodiment over the entire width of the holding element 2 but may show a width as indicated with reference designation 38, see Fig. 3.

Reference designation 30 will show an example of a so-called zero-point for the working operation or machining which shall take place on each workpiece 10. This initial position for the working machine or its tool can be formed of a part or a component on the holding element 2, as a part on the fixed jaw 9, an arranged or provided part or position on the hold- ing element 2.

When machining a workpiece or in the case of one or several similar machin- ings of several workpieces, these will be arranged to the foundation with the holding elements 2. Clamping, dimensional differences between the work- pieces and the like are eliminated with the flexible jaw 7. The machine or its tool with the sensor device searches up the initial position 30 prior to the machining of the first workpiece and carries out the operation or operations after which it can then go directly to the next workpiece for machining that workpiece, whereby the initial position 30 has been sensed by the next holding element 2, and so on, until all the workpieces 10 in the arrangement 1 have been machined in intended manner. Thus, the work- pieces do not require to be arranged or supplied to the machine in order, whereby the machine neither requires to carry out all the movements for starting and from the starting to the finishing of the machining of a workpiece.

The holding elements 2 may be formed as so-called cubes for vertical machining or vertical milling, whereby these are rotational round their axis in the usual way and are provided with jaws.

By virtue of being able to arrange the holding elements 2 at the same distance from each other the machine or the tool can quickly search for the initial position for each operation or prior to each machining and by virtue of the fact that the initial position is located on the holding element the initial position for the machine or tool and the machining carried out on the workpiece will be at the correct place, as differences in the workpieces are removed by the flexible jaw 7.

When one or several similar machinings of several workpieces 10 are to be carried out with a tool in a machine and where the workpieces show a similar dimension or configuration, holding elements 2 will be arranged with their connecting elements 14 engaged with the foundation 3 and its connecting elements 15 and 35. The number of holding elements 2, which are placed on the foundation 3, are thus one more than the number of work- pieces 10 which shall be arranged and clamped between the holding elements 2. The distance between the holding elements 2 when they are set out is regulated in such a way that the distance between these become the same as or slightly greater than the length or similar of the workpieces 10, if these are to be clamped between the holding devices 7 and 9 and their gripping faces 17 and 19 respectively. For workpieces 10 with curved, circular or similar mantle surfaces, the distance between the holding elements 2 can be shorter than the length, the diameter or similar of the workpiece, depending on the use of the recesses 16 and 26 in the second or fixed jaw 9. Irrespective of which, the holding elements 2 will be arranged when they are set out on the foundation 3 with a relative distance so that the workpieces 10 can be clamped between the holding elements 2. Thus, when using the said, third holding device 11, the distance between the holding elements 2 will be less than the length of the workpiece, the diameter or similar. It is thus the distance between the connecting, gripping or hold¬ ing faces 17, 19, 21 and 23 of the holding devices 7, 9, 11 and/or 13, with respect to the dimensions of the workpieces, shaping and the like which are critical for the positioning of the holding elements 2. Subsequently, the holding elements 2 will be anchored with the fastening devices 31 and the workpieces 10 clamped between the respective jaws and their connecting, gripping or holding faces. Any deviations in dimension or length, etc. of the workpieces will be compensated by the first, flexible holding device 7 or the third, flexible holding device 11. The zero point 30 of the holding elements 2 will thus be located at an exact relative distance from each other. A machine will be set to provide the work table, the pallet or the holding arrangement 1 with the tool or tools necessary for the operations. A machine will normally carry out the various operations in a workpiece 10 and return to an initial position for a change of workpieces, i.e. carry out the entire work cycle. With the method according to the invention the machine can instead be set so that the machine with its sensor device searches for the zero point 30 on the first holding element 2 for position¬ ing, and then carry out the intended operations in the first workpiece 10.

The machine then moves the tool to the next zero point 30 on the next or second holding element 2 for positioning, i.e. it goes directly without returning as is normally the case to the initial position and carry out the intended operations in the next or this second workpiece, and so on, until the machine and its tool have carried out the intended operations in all the arranged workpieces 10. Then the machine and the tool return to an initial position to extract the machined workpieces and if necessary insert or change workpieces 10 in the holding arrangement 1.

The arrangement can be used for certain operations and machinings where only two holding elements are used, perhaps depending on the dimension of the workpiece, etc.

Without exceeding the scope of the concept of the invention modifications of the method and the arrangement should be possible. Thus, the method and the arrangement can be used for workpieces for machining of other machines. The connecting devices of the holding elements and the foundation may be of another kind, and if cogs and rack gearings are used, which enable a simple, exact and rapid positioning of the holding elements, which come in the correct position, then other tooth pitches can be used. Other constructional designed adjustment devices for the flexible jaw or jaws may also be used. The flexible jaw or jaws could also be eliminated from certain machinings. The zero point can be arranged at another position or be formed in another part than has been proposed but shall have a fixed position, as on a fixed part. The method and the arrangement according to the invention are thus not restricted to what has been indicated by the embodiment example shown and described but only to the following claims.