Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
  • B25B23/00—Details of, or accessories for, spanners, wrenches, screwdrivers
  • B25B23/14—Arrangement of torque limiters or torque indicators in wrenches or screwdrivers
  • B25B23/141—Mechanical overload release couplings
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
  • B25B23/00—Details of, or accessories for, spanners, wrenches, screwdrivers
  • B25B23/14—Arrangement of torque limiters or torque indicators in wrenches or screwdrivers
  • B25B23/142—Arrangement of torque limiters or torque indicators in wrenches or screwdrivers specially adapted for hand operated wrenches or screwdrivers
  • B25B23/1422—Arrangement of torque limiters or torque indicators in wrenches or screwdrivers specially adapted for hand operated wrenches or screwdrivers torque indicators or adjustable torque limiters
  • B25B23/1427—Arrangement of torque limiters or torque indicators in wrenches or screwdrivers specially adapted for hand operated wrenches or screwdrivers torque indicators or adjustable torque limiters by mechanical means

Definitions

• the invention relates to a torque-boosting screwdriver with an input shaft and an output shaft, and an overload clutch for a tool.
• a screwdriver which contains a planetary gear, on the output shaft of which a torque sensor in the form of strain gauges is fastened. Furthermore, the output shaft is connected to a display part, the rotational position of which indicates the rotational position of the output shaft.
• a rotatable adjusting ring is mounted on the housing and, together with the display part, forms a screw angle display device. In addition to the function of limiting the torque, this screwdriver enables precise determination of the screwing angle in order to be able to tighten screws in a defined manner.
• the present invention has for its object to provide a torque-boosting screwdriver, in which the maximum torque can be changed in a defined manner.
• an overload clutch is provided to limit the torque, which has an adjusting device for changing the triggering torque. Furthermore, a display device for displaying the set triggering torque is provided.
• the screwdriver can therefore be used specifically for tightening screws with different tightening torques, the user being able to set the respective tightening torque beforehand and the screwdriver automatically ending its action when this tightening torque is reached.
• the tightening torque of the screw can thus be specified by the user on the screwdriver and at the same time it is ensured that the specified tightening torque is not exceeded.
• the overload clutch is provided on the input shaft of the power wrench, so that it only has to be designed in accordance with the relatively low torque of the input shaft.
• the overload clutch is preferably detachably attached to the input shaft of the transmission as a separate structural unit.
• the overload clutch can thus be removed and removed from the input shaft.
• the screwdriver can be used in different versions, namely with or without an overload clutch.
• the overload coupling increases the length of the screwdriver and increases the weight. In places where little space is available, the screwdriver can be used without the overload clutch.
• the overload clutch is simply plugged onto the input shaft or connected to the input shaft in another easily detachable manner. There is also the option for several To keep a single overload clutch ready and to attach it to the screwdriver where it is needed.
• the overload clutch means that if the tightening torque exceeds a certain value, the screw can no longer be turned further. Rather, the input shaft of the overload clutch turns through empty.
• the overload clutch preferably consists of a housing capsule which contains two disks which are pressed against one another by a spring device.
• the housing capsule here consists of two capsule parts which are screwed together, the triggering element of the overload clutch being changeable by rotating the one capsule part.
• the triggering torque can be easily set by the user.
• the capsule parts can have markings for reading the set triggering moment. You can either read the angle of rotation on a scale and then determine the torque using a table, or the scale shows the set torque directly.
• the torque exerted on the screw head depends on the reduction ratio of the gearbox. If the torque is immediately displayed on the overload clutch, this overload device can only be used for a specific screwdriver with a defined reduction ratio.
• the overload clutch has disks which interlock with sawtooth-shaped projections, so that the overload clutch is only triggered in one direction of rotation he follows.
• the vast majority of screws have right-hand threads. Such screws are tightened by turning clockwise and loosened by turning counterclockwise.
• the overload clutch is only required to tighten the screw.
• the sawtooth-shaped projections ensure that the torque is limited when tightening such screws, while any desired torque can be applied to loosen stuck screws. The torque limitation is therefore dependent on the direction of rotation. In the context of the invention, however, it is also possible to provide the projections with other profile shapes.
• the invention further relates to an overload clutch as a separate structural unit, which can optionally be used in combination with a tool.
• the overload clutch is provided on its input side and on its output side with polygonal connection elements, which can be designed, for example, as screw nuts or socket head inserts.
• Such an overload clutch can be sold as an independent component and used in conjunction with existing tools. It is particularly intended for power screwdrivers, but can also be used for screwdrivers without torque amplification.
• the overload clutch - be it as a separate unit that can be coupled to a screwdriver, or an integral part of a screwdriver provides very high accuracy that exceeds that of a conventional torque wrench many times over.
• Conventional torque wrenches have inaccuracies of up to 50%, while the inventive moderate overload safety enables the torque to be set with an accuracy of about 5%.
• the overload clutch can also be used with advantage in connection with electrical, pneumatic or hydraulic screwdrivers.
• "hard screwing” is avoided due to the quick response of the clutch.
• Fig. 3 is a side view of the overload clutch
• Fig. 4 shows a longitudinal section of the overload clutch.
• the torque-boosting screwdriver has a generally cylindrical housing 10 in which there is a planetary gear mechanism, as described in DE 296 12 693 U.
• the input shaft 11 and the output shaft 12 protrude from opposite ends of the housing 10. They run coaxially with each other.
• a tubular extension 13 is provided, through which the output shaft 12 runs.
• a support arm 14 is rotatably attached, which can be placed against a stationary abutment to the housing 10 during Secure screwing process against rotation.
• a key socket 15 is placed on the output shaft 12 and is placed on the screw to be turned.
• the gearbox contained in the housing 10 is a reduction gearbox which amplifies the torque applied to the input shaft 11 so that an increased torque acts on the output shaft 12.
• the input shaft 11 is provided with a polygon onto which a manual or power-operated rotary device 16 can be attached.
• the screwdriver is shown with an additional overload clutch 18 which is plugged onto the input shaft 11 and has approximately the same diameter as the housing 10.
• the overload clutch 18 has a housing capsule 19 which consists of two capsule parts 19a and 19b screwed together .
• the bottom of the capsule part 19a lies against the end face of the housing 10 and the connecting element 20a of the input shaft 20 protrudes from the capsule part 19b.
• This consists of a polygon to which the screwing device 16 can be attached in order to rotate the input shaft 20. If the connecting element 20a of the input shaft 20 of the overload clutch 18 has the same dimensions as the polygon of the input shaft 11 of the screwdriver, the same turning tool 16 can be used for both operating modes.
• FIG. 4 A longitudinal section through the overload clutch is shown in Fig. 4.
• the capsule part 19a is cup-shaped and the capsule part 19b represents a lid which is screwed onto an external thread of the capsule part 19a by means of an internal thread 21.
• the input shaft 20 is connected to a disk 22, which is pressed by a spring device 24 against a second disk 23.
• the disk 22 is provided on its end face with radially running sawtooth-shaped projections 26 which engage with radially running sawtooth-shaped projections 27 of the other disk 23.
• the projections 26 and 27 are designed to be complementary to one another, ie the one projection fills the gaps between the opposite projections.
• the projections 26, 27 cause the disk 23 to be rotated when the disk 22 rotates.
• the disk 23 is mounted with an extension 23a in an opening 28 in the bottom of the capsule part 19a.
• the approach 23a contains a connection element in the form of an opening 29 with a polygonal profile, into which the polygon of the input shaft 11 of the screwdriver can be inserted appropriately.
• This polygonal profile has the same cross-sectional size as that of the connecting element 20a of the input shaft 20.
• the input shaft 20 contains a recess 30 which is designed as a blind hole and which the polygon of the input shaft 11 of the screwdriver can penetrate without a rotary coupling the input shaft 20 takes place.
• the spring device 24 consists of a plate spring assembly, which is supported on the end wall of the capsule part 19b and presses against the disk 22.
• the preload of the spring device 24 is determined by the degree of tightening of the thread 21. Therefore, by rotating the capsule part 19b, the spring force with which the disks 22 and 23 are pressed against one another can be changed.
• the input shaft 20 is supported by a slide bearing 31 in the capsule part 19b.
• FIG. 3 there is a marking 32 on the circumference of the capsule part 19a and a further marking 33 in the form of an angular scale is located on the circumference of the capsule part 19b.
• the markings 32, 33 indicate the tensioned state of the spring device 24 and allow the angle of rotation to be read.
• the associated tripping torque can be determined for each angle of rotation, i.e. the maximum torque that can occur on the output shaft 12 of the screwdriver.
• the entire overload clutch 18 also rotates while the screwdriver housing 10 is held in place. If the screwing torque is so great that the triggering torque of the overload clutch is reached, then the oblique flanks of the projections 26, 27 slide on one another and the disks 22, 23 are pressed apart against the force of the spring device 24 and rotated against each other. Then the input shaft 20 rotates while the disk 23 stops.
• the capsule housing 19 is not held against rotation. It will rotate together with the disk 23 due to friction, although there is no non-rotatable connection between the capsule housing and the disk 23.
• the overload clutch 18 is connected exclusively to the input shaft 11 of the screwdriver. This connection is made by simply plugging it on. Of course, other connection techniques are also possible.
• an opening 34 is provided on the capsule part 19b, into which a rod can be inserted in order to rotate the capsule part 19b.

Applications Claiming Priority (5)

Publications (1)

Family

ID=26059477

Family Applications (1)

Country Status (3)

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Family Cites Families (6)

• 1997
  • 1997-10-02 EP EP97912099A patent/EP0929380A1/de not_active Withdrawn
  • 1997-10-02 JP JP10516247A patent/JP2001501136A/ja active Pending
  • 1997-10-02 WO PCT/EP1997/005427 patent/WO1998014309A1/de not_active Application Discontinuation

Non-Patent Citations (1)

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