DE20115251U1 - Drilling unit for woodworking machines - Google Patents

Description

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G 19785 - rets August 27, 2001

FESTO AG & Co, 73 734 Esslingen Drilling unit for woodworking machines

The invention relates to a drilling unit for woodworking machines, with at least one main body which can be moved in a feed direction and which has a plurality of lifting units arranged next to one another in a row with mutually parallel longitudinal axes, each of which can be actuated independently of one another by an actuator, wherein the free end regions of push rods of the lifting units which can be extended in the feed direction up to a working position are provided with clamping devices for drilling tools, and with a motorized rotary drive arrangement for generating a rotation of the clamping devices suitable for drilling.

Drilling units of this type are known, for example, from DE 29814105 U and generally under the name vertical drilling gear, whereby the main body is usually arranged on the head of a multi-axis NC or CNC-controlled processing machine and can be positioned by this and moved in a feed direction. The lifting units can be used to select the drilling tools required for a processing operation by moving them from a retracted rest position to an extended working position. The corresponding lifting processes are pneumatically induced in a known manner by the push rods as

Piston rods are connected to pneumatically actuated pistons.

In the known drilling units, the push rods equipped with drilling tools are not only extended pneumatically, but also held pneumatically in the working position. This means that the pneumatic pressure during the drilling process must be so high that the counterforce caused by drilling is compensated. This requires relatively large cylinders for pneumatic lifting units or correspondingly large-dimensioned lifting units for other types of drive, such as electric or magnetic drive types. A further disadvantage is that in the case of pneumatic or fluidic lifting units, a relatively long time is required to build up pressure and in turn a relatively long time is required to reduce the high holding pressure.

An object of the present invention is to improve a drilling unit of the type mentioned at the outset so that smaller-volume lifting units and a faster workflow can be realized.

This object is achieved according to the invention in that mechanical locking means are provided which lock the push rods, each extended into the working position, in the axial direction of movement at least during the drilling process.

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The main idea of the invention is that the force-locking holding of the push rods or drilling tools in the working position is replaced by a form-locking holding with mechanical means. As a result, the lifting units are only used to extend and retract the push rods equipped with the drilling tools and no longer to hold them in the working position, so that smaller-volume lifting units or lifting units with a lower lifting force can be used. The drilling movement itself is no longer dependent on the force of the lifting units, for example on the pressure level and its fluctuations. When implemented as pneumatic lifting units, the ventilation time no longer depends on reaching the final pressure in the cylinder necessary for drilling, since there is no longer any static force required. The drilling process can therefore be started much earlier. Accordingly, the ventilation time is eliminated when the push rods move back, since the lifting units can be ventilated in the locked position during the work process. Overall, this means that machining processes can be carried out much more quickly.

The measures listed in the subclaims enable advantageous further developments and improvements of the drilling unit specified in claim 1.

The locking means are advantageously designed to mesh with projections, recesses or stepped shoulders of the push rods, so that a secure, positive locking is ensured. In a preferred embodiment

In this guide form, the projections are designed as ring projections that surround the push rods.

In a preferred structural design, the locking means are designed as locking slides, in particular as actuator-operated or actuator-actuated locking slides. In this case, a common locking slide can be provided for all push rods, which has through openings spaced apart according to the distance between the push rods, with a narrower locking slot connecting each two through openings being provided. The push rods can pass through the through openings when extended and are then locked by actuating the locking slide using the locking slots.

Two alternatives have proven to be particularly suitable for locking. In the first alternative, the diameter of the through holes is slightly larger than that of the ring projections and the diameter of the locking slots is slightly larger than the diameter of the push rods.

After the ring projections have passed through the through holes, they can be locked by means of the locking slots after the locking slide has been actuated. In the second alternative, the diameter of the through holes is slightly larger than that of the push rods, and the diameter of the locking slots is slightly larger than that of the reduced diameter areas of the

Push rods. These can be ring channels or stepped shoulders.

In a preferred embodiment, the lifting units can be actuated by fluidic actuators, in particular pneumatic actuators. For this purpose, at least partial areas of the push rods are preferably designed as piston rods connected to the working cylinders that can be moved. Various practical alternative designs are available for this purpose:

In a first embodiment, motor drives of the rotary drive device are fixed directly or indirectly to the working cylinder, with the push rods meshing with drive elements of the motor drives and being axially displaceable relative to them. This means that either the entire push rods, including the pistons, can be set in rotation, or the push rods each consist of two aligned partial rods that are connected to one another via a pivot bearing, with the partial rods provided with the clamping devices being operatively connected to the motor drives of the rotary drive device and with the pivot bearings preferably being arranged in or on the pistons.

In a second alternative, the push rods have rotatably mounted drive shafts inside, which are provided with the clamping devices at one free end, with motorized

Drives of the rotary drive device are arranged to drive the drive shafts.

In a third alternative, the push rods at the tool-side end area are provided with motor drives of the rotary drive device for driving the clamping devices.

Embodiments of the invention are shown in the drawing and explained in more detail in the following description. They show:

Fig. 1 is a front view of a schematically illustrated main body of a drilling unit as an embodiment of the invention, wherein the lifting units are shown partly in the rest position and partly in the working position,

Fig. 2 is an enlarged vertical sectional view of a lifting unit according to Fig. 1 in the rest position,

Fig. 3 the same lifting unit in the working position,

Fig. 4 is a partial horizontal view of the locking slide in a position during the extension movement in the working position,

Fig. 5 the same slider in the locking position which it occupies in the working position,

Fig. 6 a second embodiment of a lifting unit in the rest position and

Fig. 7 the same lifting unit in the working position.

Fig. 1 shows a schematic representation of the drilling unit 1 of a woodworking machine as well as a section of a workpiece 2 clamped in the woodworking machine and to be drilled by the drilling unit 1.

The drilling unit 1 contains a substantially block-like main body 3, which is detachably connected to the positioning system of the woodworking machine (not shown in detail) via a holding device 4. This positioning system is generally designed to be multi-axis with NC or CNC control and enables the main body 3 to be moved and positioned for workpiece processing.

The drilling unit 1 of the embodiment is designed as a vertical drilling unit, wherein the main body 3 can be moved, among other things, in a vertical feed direction 5 indicated by a double arrow. In addition, the main body 3 can be displaced in a vertical plane at right angles to the feed direction 5 in order to position drilling tools 6 clamped to the main body 3 in a desired position vertically above the workpiece 2.

The drilling unit 1 can contain several main bodies 3 with drilling tools 6, wherein these main bodies 3 are positioned

kidney system can be conveniently moved and positioned independently of one another.

The main body 3 contains five fluid-operated lifting units 7, which are arranged in a row next to one another with longitudinal axes 8 parallel to one another. The direction of the arrangement is indicated as row direction 12. The number of lifting units 7 can of course also vary. Furthermore, a main body can also have several rows of lifting units arranged parallel or at right angles to one another.

The lifting units 7 are designed as separate structural units that are placed side by side in the row direction 12. They are held together by suitable connecting means, which in the embodiment are formed by plate-like cross members 13, 14 that are axially arranged on both sides.

According to Figs. 2 and 3, each lifting unit 7 has a housing 15 with a cuboid-like external shape, although the shape can also vary. Inside the housing 15 there is an elongated lifting chamber 16 extending in the longitudinal direction, in which an axially displaceable piston 18 is arranged. The housing 15 is closed on both ends by a cover 23, 23'. These covers can also be omitted if the cross members 13, 14 are designed appropriately.

The piston 18 is firmly connected to a piston rod 33 which runs in the longitudinal direction and serves as a push rod and which extends axially from the piston 18 in both directions.

It extends in a sealing and slidable manner through the two front housing covers 23, 23' and projects out of the housing 15 with a rear end section 34 and a front end section 35.

The piston rod 33 is completely hollow and contains a concentrically mounted drive shaft 36. At the front end of the drive shaft 36, which points downwards in the embodiment, a clamping device 43, designed for example as a chuck, is attached, by means of which the drilling tool 6 can be releasably secured.

A motor drive 46 for rotating the drive shaft 36 is attached to the rear of the piston rod 33. The motor drives 4 6 of all lifting units 7 together form a rotary drive device 44. The motor drives 4 6 are only indicated schematically in the drawing and are expediently carried by the respective associated piston rod 33 so that they follow the lifting movement caused by the movement of the piston 18.

The piston 18 movable in the housing 15 forms a single-acting working cylinder in the embodiment, i.e. when a fluid supply channel in the upper cover 23' is pressurized, the piston 18 moves downwards against the force of a compression spring 48 in the lower area of the lifting chamber, so that the clamping device 43 provided with the drilling tool 6 is extended by means of the piston rod 33 and moved into the working position, which is shown in Fig. 3. The fluid in the chamber receiving the compression spring 48

The area of the lifting chamber 16 can escape through a ventilation channel 4 9 in the lower cover 23.

A locking slide 50 is used to mechanically lock the piston rod 33 in the working position and is guided in a corresponding channel 51 in the upper cross member 14 so as to be displaceable perpendicular to the feed direction 5. The movement of the locking slide 50 can be carried out manually or by means of an electrical or fluidic actuator 52.

An annular projection 53 is fixed to the rear end section 34 of the piston rod 33 and surrounds it. The locking slide 50 is arranged in accordance with the row direction 12 of the lifting units 7 so that the piston rods 33 of the lifting units 7 each pass through a longitudinal slot 54 in the locking slide 50, this longitudinal slot 54 having a width that is slightly larger than the diameter of the piston rods 33. At certain distances a, which correspond to the distances between the lifting units 7, the longitudinal slot 54 in the locking slide 50 is expanded to form round through openings 55, the diameter of which is slightly larger than that of the annular projection 53.

During the lifting movement into the working position, the locking slide 50 is positioned as shown in Fig. 4, i.e. the ring projections 53 of the piston rods 33 can pass the locking slide 50 until they come into contact with the upper cover 23'. For this purpose, the upper cross member 14 has through openings 56 which ensure the passage of the ring projection 53 up to the upper cover 23'.

In the contact position of the ring projections 53 of those lifting units 7 that have been actuated, the locking slide 50 is moved from the position shown in Fig. 4 into the locking or locking position shown in Fig. 5, in which longitudinal slot areas of the longitudinal slot 54 lock the respective ring projection 53 or the corresponding piston rod 33 due to their smaller width. If the holding device 4 is now displaced in the feed direction 5 towards the workpiece 2 with the aid of the positioning system after the drilling tools 6 have been selected (in Fig. 1 these are two drilling tools), only the selected drilling tools 6 in the working position come into engagement with the workpiece 2. It is understood that the length of the selection stroke of the piston rods 33 indicated by the double arrow in Fig. 1 is greater than the desired machining depth in order to avoid a collision of the drilling tools 6 in the rest position with the workpiece 2.

During machining, the area of the lifting chamber 16 facing the motor drive 46 can already be vented via the fluid supply channel 47. After the machining process has ended, the locking slide 50 is moved back into the basic position shown in Fig. 4, so that the respective piston 18, the respective piston rod 33 and thus also the respective drilling tool 6 are moved back into the rest position by the force of the compression spring 48. This return movement can also be carried out with fluid support and in a more or less dampened manner.

If rotation of the piston rod 33 is to be prevented, this and/or the piston 18 can be designed with a non-round cross-section, or other known means for preventing rotation can be used.

Instead of the single-acting cylinder shown, a double-acting cylinder can of course also be used, in which the compression spring 48 can be omitted. The fluid supply channel 47 and the vent channel 49 are used alternately for pressure supply and venting. This can be done in a known manner, for example via a 3/2-way valve.

In the second embodiment shown in Figs. 6 and 7, identical or equivalent components or regions are provided with the same reference numerals and are not described again.

In contrast to the first embodiment, here there is a two-part piston rod 57 serving as a push rod, in which the rear end section 58 is non-rotatable, whereas the front end section 59 is rotatable or rotatably guided and supported. A piston 60 separates the rear end section 58 from the front end section 59 and consists of a first non-rotatable piston area 61 connected to the rear end section 58 and a second rotatable piston area 62 connected to the front end section 59 of the piston rod 57. A rotary bearing 63 is arranged between the two piston areas 61, 62. The non-

The rotatable piston region 61 has a piston seal (not shown), while the rotatable piston region 62 has a slightly smaller diameter and thus does not cause any friction with the inside of the housing 15 during rotation.

Motor drives 64 of a rotary drive device 65 are now fixed to the front cross member 13 in such a way that the front end section 59 of the piston rod 57 is arranged so as to be displaceable in a through-channel of the respective motor drive. For the drive, this front end section 59 of the piston rod 57 has a circumferential longitudinal toothing which meshes with a correspondingly toothed drive element (not shown) in the motor drive. The rear end section 58 of the piston rod 57 ends with the annular projection 53.

The extension of the desired drilling tools 6 and the locking of the piston rod 57 with regard to a longitudinal displacement are carried out in the manner already described. When the respective motor drives 64 are switched on, only the front end section 59 of the piston rod 57 connected to the piston area 62 rotates together with the clamping device 43 and the drilling tool 6. In principle, double-acting working cylinders can also be used in this embodiment.

In a modification of the second embodiment, the piston 60 can also be formed in one piece, so that the rear end section 58 is connected to the front end section 59 of the

Piston rod 57 is rigidly connected. In this case, the entire piston rod 57 is set in rotation by the motor drive 64. To avoid friction, the annular projection 53 can, for example, be designed as a correspondingly shaped pivot bearing.

In a further embodiment with a one-piece piston 60, motor drives 64 can be fixed to the front end section 59 of the piston rod 57 in such a way that they can be moved longitudinally together with the piston rod. As a result, the piston rod 57 can be guided in a non-rotatable manner and only the clamping device 43 provided with the drilling tool 6 rotates.

The invention is of course not limited to the use of fluidic lifting units, but other lifting units can also be used to extend the push rods or piston rods, such as electromotive or magnetic actuators or drives.

According to the embodiments, the rotary drive devices 44 and 65 can have separate motor drives 46 and 64 for each lifting unit, but they can also be rotated synchronously by a common motor drive.

In a modification of the embodiments shown, the locking slide 50 can be provided with corresponding, for example, ring-shaped recesses or stepped shoulders of the piston rods 33 and 57 instead of with ring projections 53.

Piston rods work together. For this purpose, the diameter of the round through openings 55 in the locking slide 50 is slightly larger than the diameter of the piston rods 33 and 57, respectively, and the slot width of the longitudinal slot 54 is slightly larger than the diameter of such ring-shaped recesses or ring channels or the diameter of the piston rods 33 and 57, respectively, after the step shoulder. Locking of the piston rods 33 and 57, respectively, is also ensured in these designs.

In a further embodiment of the second exemplary embodiment shown in Fig. 6 and 7, the longitudinal slots 54 between the round through openings 55 of the locking slide 50 can also be omitted. Alternatively or additionally, the annular projection 53 can also be omitted if another stop device is provided for determining the stop position.

Claims (12)

1. Drilling unit for woodworking machines, with at least one main body ( 3 ) which can be moved in a feed direction and which has a plurality of lifting units ( 7 ) arranged next to one another in a row with mutually parallel longitudinal axes ( 42 ), each of which can be actuated independently of one another by an actuator, wherein the free end regions of push rods ( 33 ; 57 ) of the lifting units ( 7 ) which can be extended in the feed direction ( 5 ) to a working position are provided with clamping devices ( 43 ) for drilling tools ( 6 ), and with a motor-driven rotary drive device ( 44 ; 65 ) for generating a rotation of the clamping devices ( 43 ) suitable for drilling, characterized in that mechanical locking means ( 50 ) are provided which lock the push rods ( 33 ; 57 ) each extended into the working position in the axial direction of movement at least during the drilling process. 2. Drilling unit according to claim 1, characterized in that the locking means ( 50 ) are designed to mesh with projections ( 53 ), recesses or stepped shoulders of the push rods ( 33 ; 57 ), wherein the projections ( 53 ) are preferably designed as annular projections. 3. Drilling unit according to claim 2, characterized in that the locking means ( 50 ) are designed as locking slides, wherein in particular an actuator actuation is provided. 4. Drilling unit according to claim 3, characterized in that a common locking slide is provided for all push rods ( 33 ; 57 ) as a locking means ( 50 ), which has through openings ( 55 ) spaced apart from one another according to the distance (a) of the push rods ( 33 ; 57 ), wherein a narrower locking slot ( 54 ) connecting each of the two through openings ( 55 ) is provided between them. 5. Drilling unit according to claim 4, characterized in that the diameter of the through openings ( 55 ) is slightly larger than that of the projections ( 53 ) and the width of the locking slots ( 54 ) is slightly larger than the diameter of the push rods ( 33 ; 57 ). 6. Drilling unit according to claim 4, characterized in that the diameter of the through openings is slightly larger than that of the push rods and the width of the locking slots is slightly larger than a reduced-diameter region of the push rods. 7. Drilling unit according to one of the preceding claims, characterized in that the lifting units ( 7 ) can be actuated by fluidic actuators. 8. Drilling unit according to claim 7, characterized in that at least partial regions of the push rods ( 33 ; 57 ) are designed as piston rods connected to the working cylinder movable piston ( 18 ; 60 ). 9. Drilling unit according to claim 8, characterized in that motor drives ( 64 ) of the rotary drive device ( 65 ) are fixed directly or indirectly to the working cylinder ( 15 ), wherein the push rods ( 57 ) are in tooth engagement with drive elements of the motor drives ( 64 ) and are axially displaceable relative to these. 10. Drilling unit according to claim 8 or 9, characterized in that the push rods ( 57 ) each consist of two aligned partial rods ( 58 , 59 ) which are connected to one another via a rotary bearing ( 63 ), wherein the partial rods ( 59 ) provided with the clamping devices ( 43 ) are operatively connected to the motor drives ( 64 ) of the rotary drive device ( 65 ), and wherein the rotary bearings ( 63 ) are preferably arranged in or on the pistons ( 60 ). 11. Drilling unit according to claim 8, characterized in that the push rods ( 33 ) have drive shafts ( 36 ) which are rotatably mounted in the interior and are provided with the clamping devices ( 43 ) at one free end, and that motor drives ( 46 ) of the rotary drive device ( 44 ) for driving the drive shafts ( 36 ) are arranged at the opposite end region of the push rods ( 33 ). 12. Drilling unit according to claim 8, characterized in that the push rods at the tool-side end region are provided with motor drives of the rotary drive device for driving the clamping devices ( 43 ).