Tool unit with cutter head

A tool unit is guided by a handling unit movable in several planes for cutting out recesses or bores and de-burring the work-pieces in one operational step. A de-burring cutter is mounted in a support arm for the tool which is movable about a central axis and is engaged by two spring arrangements disposed on opposing sides of the support arm and is returned to the original position following displacement. The springs of the spring arrangement can be replaced to adjust the spring pressure to various work materials and work-pieces. The cutting angle of the tool cutter is set automatically via the pressing force. Radial movement of the cutter is possible as are resilient deflection and precise return. A spring pressure pin arrangement is provided for balancing the cutter.

BACKGROUND OF THE INVENTION
 The invention concerns a tool unit which can be mounted to a handling unit,
 e.g. a robot, controlled NC shafts or the like, and which can be moved
 preferably in several planes to de-bur work-pieces made from plastic,
 rubber, aluminum, textiles (compositions), felt, wood, porcelain or other
 materials, with a tool guided along the contours of the work-piece, e.g. a
 de-burring cutter mounted, by means of a cutter support, to a support arm
 disposed for rotation about a central axis, and with an adjustable spring
 arrangement, disposed on each of the opposing sides of the support arm
 which can deflect the support arm in both directions through a
 predetermined angular or spring path to press onto the work-piece, and to
 return the tool unit and cutter head to its original position.
 DE-GM 297 10 727.5 discloses a unit with a cutter head having a very
 limited pivoting range, wherein the cutter axis has a central bearing
 only, without end positioning or defined zero position, which does not
 permit radial movement of the cutter, and which cannot be adjusted to
 softer or harder materials so that only relatively large bores or recesses
 can be de-burred.
 With plastic molded parts, the de-burring process usually has to be carried
 out directly after removal from the mold. However, the work-piece shrinks
 considerably within a relatively short cooling period, such that size
 changes due to shrinking have to be taken into consideration for
 de-burring and the cutter tool has to be positioned and guided in a
 correspondingly flexible fashion.
 It is the purpose of the invention to further develop a tool unit cutter
 head of this type in such a fashion that it can be used in an increased
 plurality of applications with improved efficiency.
 SUMMARY OF THE INVENTION
 This is achieved in accordance with the invention in that
 a) tensioned pressure springs are disposed on opposing sides of the support
 arm,
 b) the cutter support is borne on the support arm by means of ball
 bearings,
 c) a stop is disposed on the casing for centering the support arm in its
 zero position, and
 d) a stop pin is pivotably secured to the cutter support and is acted upon
 symmetrically at both ends by limiting spring pins which allow limited
 rotary movement of the cutter support on the work-piece through an
 adjustment angle of the tool, and
 e) the tool and work-piece can be adjusted relative to one another.
 Further embodiments of the invention are the subject of the dependent
 claims.
 A tool unit cutter head in accordance with the invention facilitates
 cutting out and de-burring of recesses, bores and the like on work-pieces
 of plastic, aluminum, wood, rubber, composite textiles, porcelain or
 similar materials, with one single tool unit or cutter tool and in one
 single operating step. Both large as well as small recesses and bores
 having diameters of only approximately 3 to 4 mm can be precisely cut out
 and de-burred. In accordance with the invention, the bearing of the tool
 facilitates automatic adjustment of the cutting angle via the pressing
 force, and radial movement or rotation of the cutter is possible through a
 small adjustment angle to automatically adjust an optimum cutting angle.
 The cutter is preferably provided with a cutting edge angled to achieve
 exact positioning.
 The pressure springs on both sides of the support arm are preferably
 disposed to provide a relatively long spring path.
 The springs can be replaced to change the response characteristics and to
 adjust the spring pressure to various conditions of use. The spherical or
 spherical segment shaped design of the bolt seating on one side of the
 support arm facilitates, in a particularly simple and useful manner,
 precise restoring force resilience and soft deflection of the tool to
 always allow perfect adaptation to the outer shape of the work-piece. This
 adjustment of the tool or cutter is enhanced by the spring pressure pins
 acting on the bolt disposed in the cutter support.
 The use of a ball thrust member or a latching device between the casing and
 the support arm creates final or zero positioning of the tool or of the
 tool support by the adjustable spring pins. In principle and in addition
 or alternatively thereto, an induction sensor can be disposed on the
 casing, the support arm, or the cutter to monitor the deflection of the
 support arm.
 Moreover, programming of the proposed tool unit is easier than with the
 conventional unit. The work-piece can move relative to the tool with the
 tool stationary, or the tool can move relative to the work-piece with the
 work-piece stationary. A movable work-piece can be easily guided past a
 stationary tool and, e.g. past additional tools e.g. a thread cutter or
 the like.
 The invention is described in more detail in embodiments with reference to
 the drawing.

DESCRIPTION OF THE PREFERRED EMBODIMENT
 A cylindrical casing 1 comprises an adapter flange 2 for accommodating a
 robot (not shown), an upper lid 3 accommodating the adapter flange, a
 cylindrical casing central part 4 and a lower lid 5. A pivoting or support
 arm 6 is centrally supported at 7 in the casing part 4. The support arm 6
 comprises a head part 8 with a cutter support 9 for the cutter tool 10 and
 a shaft part 11 which is pre-tensioned, in a zero position, on both sides
 by spring pressure pieces 12, 12'. The cutter support 9 comprises a
 clamping device 9' e.g. a lock nut for fixing the cutter tool 10 and is
 guided in an elongated slot 13, provided in the upper lid 3 which curves
 about the center 7 in the form of a circular segment such that the support
 arm can be pivoted through a predetermined angle of approximately
 +/-40.degree. relative to the zero position. The zero position of the
 support arm 6 is defined by an approach switch 14 or a mechanical stop
 device cooperating with a corresponding mating element 14' on the outer
 surface of the head part.
 The head part 8 is mounted in the support arm 9 via a ball bearing and
 bears a bolt or stop pin 15 which can pivot relative to the longitudinal
 axis of the support arm and whose position is pre-tensioned by springs via
 the limiting spring pressure pins 16, 16', to thereby achieve cutter
 balance. The spring pressure pins 16, 16' constitute limiting and
 adjustment pins for the stop pin 15 and allow rotation of the support arm
 9, and thereby of the tool clamping means and of the tool 10, about a
 small adjustment angle. The spring pressure pins 16, 16' can be adjusted
 to change the force exerted by the spring pressure pins on the stop pin 15
 for adjusting the cutting angle of the tool. A pressure cylinder may be
 provided instead of such a spring pressure pin to effect exact automatic
 positioning.
 The deflection of the support arm 9 is limited by the spring pressure pins
 12, 12', 19. The pressure bolts 18, 18' of the spring pressure pins act in
 opposite directions on the opposing side surfaces of the support arm 6. A
 side surface is provided with a spherical or spherical segment shaped
 elevation in the form of a support 20 which guarantees precise restoring
 forces and resilient deflection of the tool.
 FIGS. 4, 5 and 6 show a further embodiment of a cutter tool head
 corresponding to the arrangement shown in FIGS. 1-3.
 LIST OF REFERENCE NUMBERS
 1 casing
 2 adapter flange
 3 lid
 4 casing central part
 5 lid
 6 support arm
 7 bearing
 8 head part
 9 cutter support
 9' clamping device
 10 cutter tool
 11 shaft part
 12, 12' spring pressure piece
 13 elongated slot
 14 approach switch or stop device
 14' mating element
 15 bolt/stop pin
 16, 16' spring pressure pin
 16a pressure cylinder
 17, 17' flange
 18, 18' pressure bolt
 19 spring element
 20 spherical support