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
  • B25B23/142—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
• • 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
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25G—HANDLES FOR HAND IMPLEMENTS
  • B25G1/00—Handle constructions
  • B25G1/04—Handle constructions telescopic; extensible; sectional
  • B25G1/043—Handle constructions telescopic; extensible; sectional for screwdrivers, wrenches or spanners

Definitions

• the invention relates to a torque wrench that delivers an acoustic and tactile signal when a predetermined torque is reached, in particular for tightening wheel nuts.
• Torque wrenches are used to tighten screws or nuts with a precisely defined torque. When this torque is reached, a generally audible signal is generated. This usually happens in such a way that the torque is transmitted via a part loaded by a prestressed spring. When the specified torque determined by the spring preload is reached, the spring yields. The part snaps. This can be recognized by the user by a noticeable jerk or by a noise when the evasive part hits a stop.
• a special problem is the tightening of wheel nuts. If the wheel nuts are tightened too weakly, they can come loose. This can lead to very dangerous accidents. Too much torque is often applied in an effort to ensure that the wheel nuts are tightened securely. This can damage the thread and lead to tearing of the screw or deformation of alloy wheels. Wheel nuts are tightened not only by specialists in the factory or workshop, but also by laypersons, for example when changing a wheel. It is therefore desirable to tighten wheel nuts using a torque wrench. Such a torque wrench must be simple, space-saving and inexpensive, so that it can be carried as an on-board tool in any motor vehicle.
• the invention is therefore based on the object to provide a simple, space-saving and inexpensive torque wrench with which the torques required for tightening wheel nuts or the like can be conveniently applied.
• the torque wrench according to the invention is very simple in construction and can therefore be manufactured inexpensively. It can be telescopically pushed together so that it takes up little space when pushed together. On the other hand, there is a sufficiently long lever arm when the first and second parts are pulled out, so that the torques required for tightening the wheel nuts can be conveniently applied.
• the torque is transmitted from the housing via the snap device to the second part and from there to the square and the tool.
• the snap device trips.
• the first part and the housing make a small pivoting movement relative to the second part. The user feels this as a jerk.
• the second part strikes the housing, so that an acoustic signal is generated.
• a major advantage of the invention is that the snap device always responds at a predetermined torque, regardless of whether the torque wrench is pushed together or pulled apart or is in an intermediate position.
• Embodiments of the invention are the subject of the dependent claims.
• Figure 1 is a side view of a torque wrench in a partially exploded state.
• Figure 2 is an associated plan view, partly in section.
• Figure 3 is an enlarged view of the slider.
• Fig.4 shows the snap device.
• the torque wrench has a flat, rectangular housing 10.
• the housing 10 is closed at the right end in FIGS. 1 and 2 and open at the left end. At the right end sits on the housing 10, a handle part 12 made of plastic.
• the housing 10 thus forms a handle for the torque wrench.
• a first, elongated, flat part 14 of rectangular basic shape and rectangular cross section is arranged in the housing 10.
• the first part 14 is telescopic with its longitudinal edges 16, 18 well guided in the housing 10.
• a second elongated, flat part 20 of rectangular cross section lies on the first part 14.
• the second part 20 has a smaller width than the first part 14.
• the longitudinal edges of the second part are designated by 22 and 24 in FIG.
• a square 26 is firmly connected to the end of the second part 20 protruding from the housing 10, onto which a tool (not shown) can be placed. This tool engages the wheel nut or the like when using the torque wrench.
• the second part 20 is pivotally mounted on the first part 14 by means of a pivot bearing 28 aligned with the square 26.
• the square 26 sits on a base 30.
• the base has a pin 32.
• This pin 32 extends through aligned bores 34 and 36 of the first and second parts 14 and 20.
• the pin 32 is surrounded by an annular disk 38.
• the base 30 is welded to the second part 20 at 40. The end of the pin 32 is deformed so that it engages over the washer 38.
• the second part 20 is pivotally mounted on the first part 14 via a riveted connection.
• the square 26 usually has a catch 42, by means of which the tool is held on the square.
• the housing 10 in the side view of FIG. 1 is higher than the total thickness of the two superimposed first and second parts 14 and 20.
• a rectangular plate 46 which is short in comparison to the length of the second part 20 is inserted and secured in the housing 10. This securing takes place in that the plate 46 has a bore 48 into which an indentation 50 of the housing wall engages.
• the resilient snap device has two inclined surfaces 52 and 53 inclined to the longitudinal direction of the second part 20. These inclined surfaces 52 and 53 are provided on a slide 54 which is guided on the second part 20 so as to be longitudinally displaceable.
• the snap device contains a pretensioned spring 56 acting in the longitudinal direction of the second part 20 on the slide 54.
• a stop surface 58 lying in the effective direction of the spring 56.
• a roller 60 bears against the stop surface 58.
• the roller 60 is pressed by the spring 56 via the slider 54 against the adjacent inner wall 64 of the housing 10.
• the second part 20 is held on the opposite side with the edge 24 in contact with the opposite inner wall 66 of the housing 10.
• the torque to be applied is transmitted from the handle part 12 via the housing 10 to the roller 60 and from there to the slide 54.
• the slider 54 does not evade initially because it is preloaded by the spring 56.
• the torque is transmitted to the second part 20 and from there via the square 26 and the tool (not shown) to the wheel nut to be tightened.
• a predetermined value which is determined by the bias of the spring 56 and the position of the roller 60 relative to the slider 54
• the slider 54 deflects against the action of the spring 56.
• the second part 20 then strikes the inner wall 64 of the housing 10, generating an acoustic and tactile signal.
• the second part 20 has a lateral cutout 68 in the region of its inner end extending into the housing.
• This section is limited by the stop surface 58, a spring abutment surface 70, which lies opposite the stop surface 58, and a guide surface 72 which extends in the longitudinal direction of the second part 20 between the stop surface 58 and the spring abutment surface 70.
• the slider 54 has a prismatic head part 74.
• the inclined surfaces 52 + 53 are attached to the head part 74 as side surfaces thereof.
• the head part 74 lies with a further side surface 76 on the guide surface 72.
• the prestressed spring 56 rests on the one hand on the spring abutment surface 70 and on the other hand on a further side surface 78 of the prismatic head part 72.
• a transverse bore 80 is made in the second part 20 in the area of the spring abutment surface 70.
• the transverse bore 80 is cut by the spring abutment surface 70 so that it is open towards the cutout 68.
• a shaft 82 is attached to the head part 74, which is surrounded by the spring 56 and projects into the cut transverse bore. The spring 56 is guided through this shaft 82.
• the cut transverse bore 80 allows a limited movement of the shaft 82 relative to the spring abutment surface 70 when the snap device is triggered, that is to say when the roller 60 pushes the head part 72 away.
• a bore 84 is made in the second part 20.
• a pin 86 is seated in this bore 84. This pin 86 strikes the end face of the plate 46 when the first and second parts 14 and 20 are pulled out and limits the telescopic movement.
• the mode of operation of the snap device can best be seen from FIGS. 3 and 4. 3, the two inclined surfaces 52 and 53 form an edge 88.
• the inclined surface 52 is relatively flat. It forms an angle of 50 ° with the plane 90 perpendicular to the longitudinal direction of the slider 54.
• the inclined surface 53 is against it relatively steep. It forms an angle of 20 ° with plane 90.
• the roller 60 lies against the edge 88.
• a force P is exerted on the roller 60 via the inner wall 64.
• a force F of the spring 56 counteracts this force P.
• the force component exerted by this force F on the roller 60 against the force P becomes smaller, the further the roller 60 when the slide 54 dodges against the action of the spring 56 downward in FIG. 4 into the space between the slide 54 and the stop surface 58 is moved into it.
• the inclined surface 52 enables lower demands on the tolerances for the position of the edge 88.
• the force P, at which the spring 56 yields, is first determined by the inclination of the inclined surface 52, against which the roller 60, as shown, rests. When the spring 56 and the slider 54 give way, the roller 60 rolls over the edge 88, the “knee lever effect” described occurring.
• the inclined surface 53 ensures that after the force P ceases, the roller 60 returns to its starting position under the influence of the spring 56.
• the snap device shown in FIG. 5 could also be provided. With this snap device there are no inclined surfaces Chen provided but only an edge 94 corresponding to the edge 88 of FIG. 4. The described toggle lever effect also occurs here.
• the snap device responds to a certain force exerted on the roller 60.
• This force acts on a fixed lever arm, namely the distance between the roller 60 and the axis of the pin 32.
• Force times lever arm determines the torque at which the snap device responds and emits the acoustic and tactile signal. This is irrespective of whether the first part 14 and the second part 20 have been inserted into the housing 10 or have been wholly or partly pulled out of the housing 10.
• the length of the lever arm effective for the user can be adapted to the needs without this influencing the predetermined "target torque". It is also ensured that z. B. by incomplete pulling of the parts 14 and 20 from the housing 10, the snap device responds at an incorrect torque and thereby the wheel nuts are erroneously tightened with an incorrect torque.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Details Of Spanners, Wrenches, And Screw Drivers And Accessories (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6324300

Family Applications (1)

Country Status (5)

Families Citing this family (3)

Family Cites Families (10)

• 1987
  • 1987-03-28 DE DE19873710401 patent/DE3710401A1/de not_active Withdrawn
• 1988
  • 1988-03-21 JP JP50289488A patent/JPH02502802A/ja active Pending
  • 1988-03-21 EP EP19880902836 patent/EP0356439A1/de not_active Ceased
  • 1988-03-21 WO PCT/EP1988/000228 patent/WO1988007435A1/de not_active Application Discontinuation
  • 1988-03-28 ES ES8800949A patent/ES2009890A6/es not_active Expired

Non-Patent Citations (1)

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