Screwdriver adapter

A screwdriver adapter (1) is provided with a receiving part (3) having an interior space (5). At the open end of the pot-shaped receiving part (3) there is inserted a nut-shaped element (2) in torsionally rigid and axially secured relationship. Adjoining the tool driving means (6) there is disposed a channel (8), which passes axially through the nut-shaped element (2) and extends as far as the interior space (5) of the receiving part (3). Drive portions broken off by overtorquing a screw in the tool driving means (6) can travel via the channel (8) into the interior space (5) of the receiving part (3), where they can be collected until an emptying process.

BACKGROUND OF THE INVENTION
 The invention relates to a screwdriver adapter, with a drive part which
 fits a screwdriver and with a nut-shaped element containing a tool driving
 means for driving in a screw having a drive portion that can be broken
 off, twisted off or torn off by intentional overtorquing, the nut-shaped
 element being provided with a channel extending from the tool driving
 means.
 To create an overtorquing safeguard for screws, or in other words a firm
 seat for screws without causing damage to the threaded region, the
 possibility is provided among others that the drive portion of a screw or
 an appropriate part of the drive portion is broken off, twisted off or
 torn off during final setting of a screw, whereupon the setting process is
 ended. Usually such an overtorquing safeguard is created by providing a
 predetermined breaking point. The drive portions broken off, twisted off
 or torn off in this case cannot be left simply to be around thereafter,
 regardless of the type of processing, since damage to the surface of the
 fastened workpieces or coverings disposed thereover can ensure under
 certain circumstances.
 From European Patent Application EP 0723086 A there is already known a
 screwdriver adapter which is provided with a drive part to fit a
 screwdriver and a nut-shaped element constituting a tool driving means.
 This adapter for driving in a screw is provided with a drive portion that
 can be broken off, twisted off or torn off by intentional overtorquing.
 The nut-shaped element is provided with a channel extending from the tool
 driving means, through which channel a drive portion broken off from a
 screw can fall out, first in axial direction and then in radial direction.
 At the rear end of the nut-shaped element provided with the tool driving
 means there is disposed a free space, which is open over an angle of more
 than 180.degree., so that the broken-off drive portion can fall out freely
 after exiting the channel.
 BRIEF SUMMARY OF THE INVENTION
 The object of the present invention is therefore to provide a screwdriver
 adapter with which the broken off, twisted off or torn off drive portions
 of a screw can be received and collected.
 According to the invention, this is achieved in that the channel opens into
 an interior space of a pot-shaped receiving part for drive portions broken
 off, twisted off or torn off from a screw, the open end of this receiving
 part being closed from the nut-shaped element, which is inserted in
 torsionally rigid and axially secured relationship to the channel passing
 through the nut-shaped element, and its opposite end being equipped with
 the drive part which fits a screwdriver.
 By this feature according to the invention there is created the possibility
 that an appropriate drive portion can be transferred immediately after
 being broken off, twisted off or torn off through a channel into an
 interior space of a receiving part, where a plurality of such separated
 drive portions can be received. As soon as an appropriate quantity of such
 drive portions has been collected in the interior space of the receiving
 part, it can be emptied. In this way additional working effort for picking
 up and collecting the separated drive portions is obviated.
 Since the receiving part is pot-shaped, wherein its open end is closed from
 the nut-shaped element, which is inserted in torsionally rigid and axially
 secured relationship, to the channel passing through the nut-shaped
 element, the nut-shaped element itself can be removed in order to empty
 the receiving part, ensuring that no additional features with
 corresponding openings in the receiving part have to be provided. The
 receiving part can therefore be constructed with simple structure, for
 practical purposes substantially as a hollow cylinder, which is closed at
 the open end by the nut-shaped element itself.
 Further possibilities are opened up precisely by this interchangeable
 holder. For example, it is possible in one alternative embodiment for the
 nut-shaped element to be made with a tool driving means at both of its
 ends and to be insertable into the receiving part in torsionally rigid and
 axially secured relationship via one of the two ends, which are axially
 separated from each other. To achieve, for example, longer service life of
 the nut-shaped element, it is therefore possible to design the same with a
 tool driving means at both ends thereof.
 In this connection it is particularly advantageous for two differently
 shaped tool driving means to be provided at the two ends of the nut-shaped
 element for engaging with differently shaped drive portions. Thus the
 nut-shaped element can be used for various drive portions of screws, and
 especially for screws which have two different drive portions at the same
 time. In such a case, the one drive portion is designed to be broken off,
 twisted off or torn off, whereas the other drive portion provides the
 ability, should the need arise, of subsequently loosening the screw again
 after it has already been finally set. These two drive portions however,
 have in principle different shapes and/or sizes, and the respective
 desired tool driving means can be formed at the two ends of the nut-shaped
 element. Of course, only one tool driving means together with the
 receiving part is needed while the screw is being driven in, since only
 one drive portion to be broken off, twisted off or torn off during the
 driving-in process is provided on any given screw. The possibility thereof
 exists, however, of using the adapter for the screwdriver universally,
 although for such screws the frequency of the driving-in process is
 substantially greater than the process of extraction of screws.
 To ensure that the screw to be driven in can be appropriately held together
 with its drive portion in the nut-shaped element until the screw has been
 set on the workpiece, it is suggested according to the invention that
 holding elements engaging resiliently in radial direction in the recess of
 the tool driving means be provided in the region of at least one of the
 tool driving means of the nut-shaped element. In this way the possibility
 is achieved that the screw can be inserted captively and set better via
 its drive portion by appropriate application of force.
 To ensure that the torque can be transmitted properly from the adapter to
 the screw, a torsionally rigid holder is required between receiving part
 and nut-shaped element. To achieve this, one alternative embodiment
 provides that a circumferential shoulder with a toothed profile, polygonal
 structure or analogous shape is formed approximately in the middle region
 relative to the axial length of the nut-shaped element, and that a
 complementary toothed profile, polygonal structure or analogous shape is
 provided at the open rim region of the pot-shaped receiving part in order
 to forcibly turn the nut-shaped element. Thereby there is created, for
 transmitting the necessary torque, a simple joint which can be made by
 inserting the receiving part and the nut-shaped element together in axial
 direction. Thus there is no need for a complex assembly or for any kind of
 immobilization of screws or couplings.
 The simple possibility of mounting the nut-shaped element in a receiving
 part is improved in particular in that an annular groove is formed at a
 distance from the respective end of the nut-shaped element, in which
 groove there engages, to hold the nut-shaped element axially, a resilient
 annular element such as an O-ring, inserted in a groove in the inside wall
 of the pot-shaped receiving part. Upon insertion to form the torsionally
 rigid joint, an axially secure relationship between the two parts, or in
 other words the nut-shaped element and the receiving part, can
 simultaneously be achieved. Since the axial holder does not have to
 transmit any large forces, simple assembly and disassembly of the
 nut-shaped element is possible, on the one hand for changing the tool
 driving means, which are different at the two ends, and on the other hand
 for emptying the drive portions collected in the interior space of the
 receiving part.

DETAILED DESCRIPTION OF THE INVENTION
 An adapter 1 for a screwdriver comprises, in the manner according to the
 invention, a receiving part 3 and a nut-shaped element 2. Adjoining
 receiving part 3 is a drive portion 4 which fits a screwdriver and with
 which the adapter can be forcibly turned by a screwdriver and held axially
 therein.
 This adapter according to the invention is designed to be used in
 particular for driving in screws 17, which are provided with a drive
 portion 18 that can be broken off, twisted off or torn off by intentional
 overtorquing. For this purpose nut-shaped element 2 has a tool driving
 means 6, which is constructed to correspond substantially to drive portion
 18 of screw 17. Adjoining tool driving means 6 there is disposed in
 nut-shaped element 2 a channel 8, which opens into an interior space 5 of
 receiving part 3, which advantageously is pot-shaped.
 When screw 17 is now set and there is applied a torque, which in the case,
 for example, that a predetermined breaking point is disposed at the end of
 drive portion 18 adjacent to the screw, causes drive portion 18 to be
 twisted off, then adapter 1 could well be turned further without further
 turning of screw 17 itself, although the driving-in process for the screw
 is then ended. Torn off or twisted off drive portion 18 then travels
 directly into channel 8 and from there into interior space 5 of receiving
 part 3. Twisted off receiving parts 18 are thus consecutively received in
 channel 8 and in interior space 5 adjoining it.
 A simple alternative is achieved, when receiving part 3 is pot-shaped, in
 which case nut-shaped element 2 itself closes off the open end of
 receiving part 3 for practical purposes, and so only channel 8 above tool
 driving means 6 is still open into interior space 5.
 Of course, a joint with appropriate torsional rigidity must be created
 between inserted nut-shaped element 2 and receiving part 3, and axial
 securing means must also be provided to ensure that nut-shaped element 2
 does not fall or be forced inadvertently out of receiving part 3.
 Heretofore reference has been made to a nut-shaped element having a tool
 driving means 5 at one of its ends. Since nut-shaped element 2 itself
 forms the closure of receiving part 3, another advantageous construction
 can be additionally created in that the corresponding parts for
 torsionally rigid and axially secured disposition of the nut-shaped
 element are made as mirror images, as it were, at two different ends. In
 this case it is possible to provide, at the two ends of nut-shaped element
 2 separated by an axial distance, tool driving means 6 and 7, which are
 expediently shaped such that they can accommodate different structures of
 drive portions 18 and 19. In special screw 17 according to FIG. 2, there
 are provided two drive portions 18 and 19, of which drive portion 18 can
 be twisted off or torn off by virtue of a predetermined breaking point,
 and drive portion 19 is used in order to be able to extract the screw once
 again if the need arises. For this purpose there is required a separate
 drive portion 19, which for practical purposes is also substantially
 larger-sized and cannot be grasped with the same tool driving means 6 of
 nut-shaped element 2. In the presented diagram, drive portion 18 is
 constructed, for example, as a square, while drive portion 19 is
 hexagonal. Accordingly, tool driving means 6 will be used for driving in
 the screw, while tool driving means 7 will be used for extracting screw 17
 should the need arise.
 It would also be entirely conceivable, however, to provide two identically
 shaped tool driving means 6 and 7 at the two ends of nut-shaped element 2,
 in order to double the service life of a single nut-shaped element 2,
 which is achieved by reversing the nut-shaped element after prolonged use
 of one end thereof.
 To ensure that screw 17 inserted beforehand with its drive portion 18 is
 adequately held axially in the nut-shaped element until the screw is
 finally set or partly driven into the corresponding workpiece, a holding
 element 15, also engaging resiliently in known manner in radial direction
 in the recess of tool driving means 6, can be provided in nut-shaped
 element 2 according to the invention. This holding element 15, which can
 have the form, for example, of a ball or a stud, can be urged radially
 toward the tool driving means by an appropriate resilient element 16.
 Appropriate measures must be provided to ensure that nut-shaped element 2
 can be forcibly turned by and secured axially in receiving part 3. In the
 illustrated alternative embodiment, the nut-shaped element is equipped
 with a circumferential shoulder, which is disposed approximately in the
 middle region relative to the axial length of nut-shaped element 2. At its
 circumstance, shoulder 9 is advantageously provided with a polygonal
 structure 11. At the open rim region of pot-shaped receiving part 3 there
 is then provided a complementary polygonal structure 10 in the form of a
 complementary opening for forcibly turning nut-shaped element 2. Moreover,
 at a distance from the respective end of nut-shaped element 2 there is
 formed an annular groove 12, in which there engages a resilient annular
 element 13 in a groove 14 in the inside wall of pot-shaped receiving part
 3 to ensure that nut-shaped element 2 is held axially. A kind of O-ring
 can also be used for this purpose. It is now immaterial with which end
 nut-shaped element 2 is thrust into interior space 5 of receiving part 3,
 since forced turning is always ensured by the complementary shape in the
 region of shoulder 9 and the corresponding disposition at the free end of
 receiving part 3, as is an axially secure relationship by annular element
 13 and associated grove 12. The screwing-in pressure in axial direction is
 transmitted through shoulder 9, since this is braced against a stop 20 of
 receiving part 3.
 Instead of a polygonal structure 11 or 10 for mutual forced turning, it is
 also possible to provide, for mutual joining, a type of toothed profile by
 means of which nut-shaped element 2 and receiving part 3 can engage
 interlockingly in each other.
 As already explained, a complementary tool driving means 6 is inherently
 adequate at one end of nut-shaped element 2, so that nut-shaped element 2
 itself could be made substantially shorter. In such a case, the only
 requirements are appropriate holding by annular element 13, which engages
 in a groove 14, and the disposition of shoulder 9 with the complementary
 toothed profile or polygonal structure or analogous shape.
 Tool driving means 6 and 7, which are very different precisely in size and
 shape, have the positive result that there can adjoin tool driving means 6
 a channel 8 with cross section larger than that of the said drive, in
 order to facilitate removal of torn off drive portion 18.
 Several other alternative embodiments of the manner in which nut-shaped
 element 2 can be joined to receiving part 3 are conceivable. It would also
 be conceivable, for example, to provide nut-shaped element 2 with an
 external circumferential groove or with pot-shaped structure, in order to
 be able to engage over the rim region of the pot-shaped receiving part.
 Under certain circumstances the corresponding joint would then be formed
 not on the inside of the pot-shaped receiving part but on the outside wall
 of receiving part 3. In this way a joint could be achieved, for example,
 by means of a threaded screw coupling, by means of a kind of quarter-turn
 fastener or in similar way by means of resilient annular elements and
 toothed profiles, polygonal structures or analogous shapes of various
 geometries.
 The adapter according to the invention still proves to be particularly
 advantageous, since it does not absolutely have to be used for driving in
 screws, or it can be used only when drive portions to be broken off,
 twisted off or torn off are present. By virtue of the extremely simple
 construction and the special structure of the nut-shaped element itself,
 such an adapter can be used for driving in any kind of screws.