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
  • B25B23/02—Arrangements for handling screws or nuts
  • B25B23/08—Arrangements for handling screws or nuts for holding or positioning screw or nut prior to or during its rotation
  • B25B23/10—Arrangements for handling screws or nuts for holding or positioning screw or nut prior to or during its rotation using mechanical gripping means
  • B25B23/105—Arrangements for handling screws or nuts for holding or positioning screw or nut prior to or during its rotation using mechanical gripping means the gripping device being an integral part of the driving bit
  • B25B23/108—Arrangements for handling screws or nuts for holding or positioning screw or nut prior to or during its rotation using mechanical gripping means the gripping device being an integral part of the driving bit the driving bit being a Philips type bit, an Allen type bit or a socket

Definitions

• the invention relates to a screwdriver with a screw holder, according to the preamble of patent claim 1.
• the bone or, for example, a spinal segment should also be exposed without exposing the area treating parts are operated on (minimally invasive technique).
• clamping pliers for example, are no longer suitable for inserting bone or pedicle screws.
• a screwdriver with means for holding a screw is known from EP 0 458 449 RYDER.
• This known screwdriver comprises a longitudinal shaft part with a free end, which can be inserted into a corresponding recess in a screw head.
• the elastic means which are used to clamp the screws, are embedded in a groove parallel to the longitudinal axis and consist of a compressible elastomer. Since the elastic means protrude radially beyond at least one side surface of the shaft part in the uncompressed state, they are compressed into a complementary recess when the shaft part is inserted and press against the side wall of the recess, as a result of which the screw head is held on the shaft part.
• a disadvantage of this configuration of the elastic means is that when the shaft part is inserted into a complementary recess in a screw head, the elastic means could not be compressed but pushed away from the front end of the shaft part.
• the invention seeks to remedy this.
• the invention has for its object to provide a screwdriver with an elastic screw holder, so that the screw holder cannot be bent back when inserting the screwdriver into a suitable recess on a screw head.
• the elastic means should be designed so that the screw holder when Pulling off the screw head from the screwdriver tends to expand radially, which additionally increases the pulling force.
• the elastic means should also be producible from metallic materials.
• the invention solves the problem with a screwdriver with a screw holder, which has the features of claim 1.
• the inventive screwdriver with screw holder essentially comprises a shaft, which is connected at its rear shank portion with driving means, such as a handle or a machine, and a forward shaft section, which in a form suitable for screwdriver recess, for example a hexagon socket or Torx on a screw head is insertable, as well as a spring element which is elastically deformable transversely to the longitudinal axis of the front shaft segment and comprises at least one fixed segment which can be connected to the shaft and at least one elastic segment.
• the elastic segment is preferably arranged in a groove parallel to the longitudinal axis of the shaft segment, so that in the unloaded state of the spring element at least part of the elastic segment projects beyond the cross-sectional area of the shaft segment considered parallel to the longitudinal axis.
• the fixed segment of the spring element is fastened in a bore which penetrates into the front surface of the front shaft segment.
• the bore has a bore axis which includes an angle of 90 °> ⁇ > 0 ° with the longitudinal axis of
• the advantages achieved by the invention are essentially to be seen in the fact that thanks to the design of the spring element according to the invention, when the front shaft segment is inserted into a complementary recess in a screw head, the spring element is pressed and elastically deformed, even if the spring element is relatively unloaded protrudes far beyond the cross section of the front shaft segment. As a result, a relatively large retention force can be exerted on the screw head by the screw holder without there being a risk that the elastic means will be bent.
• the angle ⁇ enclosed between the bore axis and the longitudinal axis of the shaft is between 35 ° and 55 °. This configuration with an angle ⁇ that is not too flat prevents the spring element from being pulled out of the bore when the screwdriver is pulled out of the screw head. The choice of a not too steep angle enables or simplifies the assembly of the spring wire on the pin.
• the spring element protrudes perpendicularly to the longitudinal axis by a height H over the cross-sectional area of the front shaft segment considered parallel to the longitudinal axis.
• This height H is preferably between 0.2 mm and 0.8 mm. Due to the design of the screw holder as a spring wire with a fixed segment, which is pressed into a bore penetrating from the end face into the front shaft segment, the height H can be selected to be greater than with screw holders which are arranged free-standing on the front shaft segment. The greater height H results in greater deformation of the spring element when it is inserted into a corresponding recess on a screw head, as a result of which a higher clamping force of the screw holder can be achieved.
• the ratio Qi / Q 2 between the cross-sectional area Qi of the spring element and the cross-sectional area Q 2 of the front shaft segment is preferably between 0.06 and 0.01.
• Such cross-sectional relationships are produced, for example, by an external hexagon with a wrench size of 3.5 mm and a spring wire with a diameter of 0.8 mm or by an external hexagon with a wrench size of 2.5 mm and a spring wire with a diameter of 0.3 mm ,
• FIG. 1a shows a longitudinal section through the preferred embodiment of the screwdriver according to the invention with screw holder
• FIG. 1 b is a view of the embodiment of the screwdriver according to the invention with screw holder shown in FIG. 1a;
• FIGS. 1a and 1b shows a front view of the embodiment of the screwdriver according to the invention with screw holder shown in FIGS. 1a and 1b;
• Fig. 2 shows a longitudinal section through a further embodiment of the screwdriver according to the invention with screw holder.
• the screwdriver 1 with screw holder shown in FIGS. 1a-1c essentially comprises a longitudinal shaft 2 with a longitudinal axis 3, a rear shaft segment 10 and a front shaft segment 9, which has an end face 18 perpendicular to the longitudinal axis 3 and a spring element 6, which is elastically deformable transversely to the longitudinal axis 3.
• the front shaft segment 9 is complementary to the recesses on the screw heads which are to be used, for example in the form of an external hexagon.
• the spring element 6 is a bent metallic spring wire with a first cross-sectional area 15 and comprises a fixed segment 12 coaxial with the central axis 14 and an elastic segment 13 also coaxial with the central axis 14.
• the fixed segment 12 of the spring element 6 is pressed into a bore 7, which from the end face 18 of the front shaft segment 9 penetrates into the shaft 2.
• the elastic segment 13 runs in an S-shape from the exit of the bore 7 first radially on the end face 18 and then in a groove 8 which is embedded in the shaft 2 parallel to the longitudinal axis 3.
• the spring element 6 projects from the front shaft segment 9 radially out of the groove 8 and in the unloaded state protrudes beyond the second cross-sectional area 16 of the front shaft segment 9 by a height H measured perpendicular to the longitudinal axis 3. This height is reduced against the rear shaft segment 10.
• the bore axis 17 of the bore 7 intersects the end face 18 of the shaft 2 at an angle, so that an angle ⁇ is included between the bore axis 17 and the longitudinal axis 3.
• the spring element 6 is pressed with its fixed segment 12 into a bore 7 in the front segment 9 of the shaft 2.
• the bore axis 17 of this bore 7 forms an angle ⁇ with the longitudinal axis 3 of the screwdriver, the bore 7 opening into the end face 18 of the shaft 2.
• the elastic segment 13 of the spring element 6 is bent in such a way that it protrudes over part of its length perpendicular to the longitudinal axis 3 by a height H above the pin 2.
• This height H reaches its maximum at a depth T from the end face 18 of the shaft 2, which depth is considered parallel to the longitudinal axis 3, the depth T being between 0.5 mm and 3 mm.
• the central axis 14 of the spring element 6 including an angle ⁇ between 3 ° and 30 ° with the longitudinal axis 3 in this part of the elastic segment 13 and the spring element 6 being receivable in the groove 8 is.

Landscapes

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

Applications Claiming Priority (1)

Publications (1)

Family

ID=4358222

Family Applications (1)

Country Status (6)

Cited By (3)

Families Citing this family (12)

Family Cites Families (9)

• 2001
  • 2001-07-12 BR BR0117057-0A patent/BR0117057A/pt not_active Application Discontinuation
  • 2001-07-12 CA CA002460626A patent/CA2460626A1/en not_active Abandoned
  • 2001-07-12 WO PCT/CH2001/000437 patent/WO2003006210A1/de active Application Filing
  • 2001-07-12 EP EP01944867A patent/EP1404492A1/de not_active Withdrawn
• 2002
  • 2002-06-19 AR ARP020102296A patent/AR034598A1/es unknown
• 2004
  • 2004-01-12 US US10/755,894 patent/US6971293B2/en not_active Expired - Fee Related

Non-Patent Citations (1)

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