SOCKET FOR A TIGHTENING TOOL

Abstract

Disclosed is a socket unit comprising a first body portion comprising a first rear end portion for connection to the output shaft of a power tool and a front end portion adapted for engagement with a screw joint and a second body portion comprising a second rear end portion for connection to the output shaft of the direct driven power tool or a second front end portion adapted for engagement with a screw joint. The second body portion is at least partly arranged in the first body portion, and a relative rotation between the first and second body portions is allowed, such that one of the first and second body portions may rotate over a predetermined allowable angular range when the other is in engagement with the screw joint. The present specification also relates to a corresponding method, power tool and computer readable storage medium.

Claims

1. A socket unit (1) for a power tool adapted to perform a tightening operation, comprising a first body portion (10); and a second body portion (20); said first body portion comprising one of a rear end portion (10a) for connection to the output shaft of a power tool and a front end portion adapted for engagement with a screw joint and said second body portion comprising the other of said rear end portion for connection to the output shaft of a power tool and said front end portion (20b) adapted for engagement with a screw joint; wherein said second body portion is at least partly arranged in said first body portion, and wherein a relative rotation between said first and second body portion is allowed, such that one of said first and second body portion may rotate over a predetermined allowable angular range when the other of said first and second body portion is in engagement with said screw joint.

2. Socket according to claim 1, wherein said first body portion is a tubular body portion and comprises an open cavity (11) arranged at a first end of the body portion, and wherein said second body portion is arranged at least partly in said open cavity.

3. Socket according to claim 1 or 2, wherein said first portion comprises a first end face (12) and said second body portion comprises a second end face (22) and wherein said first and second end faces lie in a common plane.

4. Socket according to any of the preceding claims, wherein said first body portion comprises engaging means (13a,13b) adapted to engage a corresponding engaging means (23a,23b) comprised by said second body portion in order to provide a mechanical stop limiting said relative rotation.

5. Socket according to any of the preceding claims, wherein said first body portion comprises a first radial protrusion (13a;13b) projecting radially inward forming a first shoulder and wherein said second body portion comprises a second radial protrusion (23a;23b) forming a second shoulder projecting radially outwards, such that said first and second shoulder may engage to stop a relative rotation between said first and second body portion.

6. Socket according to claim 5, wherein said second body portion comprises a substantially cylindrical first end section (24) having two protrusions (23a; 23b) projecting radially outwards.

7. Socket according to claim 6, wherein said second body portion comprises a substantially cylindrical second end section (25) having a diameter equal to the diameter of said first end body portion and the radial extension of said two protrusions projecting radially outwards.

8. Socket according to any of claims 5-7, wherein said open cavity of said first body portion comprises an inner cylindrical surface (11a) and wherein said surface comprises two protrusions (13a; 13b) projecting radially inward.

9. Socket according to any of the preceding claims 5-8, wherein said first shoulder comprises a substantially flat engaging surface (16) extending in said radial direction and said second shoulder comprises a second substantially flat engaging surface extending (26) in said radial direction, such that said first and second engaging surface may make contact along said flat engaging surfaces thereby providing said mechanical stop limiting said relative rotation.

10. Socket according to any of the preceding claims, wherein said first body portion comprises a rear end portion (10a) for connection to the output shaft of a power tool and said second body portion comprises a front end portion (20b) adapted for engagement with a screw joint.

11. Socket according to any of the preceding claims 1-9, wherein said second body portion comprises a rear end portion (10a) for connection to the output shaft of a power tool and said first body portion comprises a front end portion (20b) adapted for engagement with a screw joint.

12. Socket according to any of the preceding claims, wherein said allowable range for said relative rotation is 50-120°, preferably 90-110°.

13. A method in a hand held electric tool for performing tightening operations where torque is delivered in pulses to tighten a screw joint, the hand held electric tool comprising an output shaft, the method comprising the steps of: providing a first torque pulse on said output shaft in said tightening direction; rotating said output shaft in a direction opposite to the tightening direction over a predetermined angular interval; and providing a second torque pulse on said output shaft in said tightening direction.

14. A hand held electric tool for performing tightening operations where torque is delivered in pulses to tighten a screw joint, wherein the hand held electric pulse tool comprising an output shaft and is adapted to engage a socket according to any of the preceding claims 1-12, the tool being operative to; provide a first torque pulse on said output shaft in said tightening direction; rotate said output shaft in a direction opposite to the tightening direction over a predetermined angular interval range; and provide a second torque pulse on said output shaft in said tightening direction.

15. A computer readable storage medium having stored there on a computer program which when run in the power tool causes the power tool to perform the method of claim 13.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The invention will be described in the following illustrative and non-limiting detailed description of exemplary embodiments, with reference to the appended drawing, on which

[0035] FIG. 1 is a longitudinal cross sectional view of an exemplary socket unit according to a first embodiment.

[0036] FIG. 2 is a transverse cross sectional view of an exemplary socket unit.

[0037] FIG. 3 is a perspective view of the first body portion of a socket unit according to a first embodiment.

[0038] FIG. 4 is a perspective view of the second body portion of a socket unit according to a second embodiment.

[0039] FIG. 5 is a perspective view of a snap ring comprised by a socket unit according to a second embodiment.

[0040] FIG. 6 illustrates a flow chart according to an exemplary embodiment of the present disclosure.

[0041] All figures are schematic, not necessarily to scale and generally only show parts which are necessary in order to elucidate the invention, wherein other parts may be omitted or merely suggested.

DETAILED DESCRIPTION OF THE INVENTION

[0042] An exemplary socket unit 1 according to a first embodiment for use with a tightening tool according to a first embodiment is shown in a longitudinal cross sectional view in FIG. 1. The socket unit 1 comprising a first body portion 10 and a second body portion 20. In the illustrated embodiment, the first body portion comprises a rear end portion 10a for connection to the output shaft of a power tool whereas the second body portion 20 comprises a front end portion 20b adapted for engagement with a screw joint.

[0043] The first body portion 10 may further be described as a tubular body comprising an open cavity 11 arranged at a front end 10b in which the second body portion 20 is arranged. The open cavity is delimited at an upper end of a delimiting wall extending through the tubular body 10. Further, the first body portion 10 comprises a first end face 12 and the second body portion 20 comprises a second end face 22 which lie in a common plane. It follows that the axial length of the cavity 11 is equal to the axial length of the second body portion such that the second body portion 20 is arranged completely within the cavity 11.

[0044] The second body portion 20 is further arranged in the cavity such that a relative rotation between the first and second body portion is allowed. Hereby, the first body portion 10 may rotate over a predetermined allowable angular range also for example when the second body portion 20 is in engagement with a screw joint, in or close to snug, thereby hindering any rotation of the second body portion 10. In the illustrated embodiment, the socket unit comprises a pin 30, e.g. a needle roller 30, rotatably connecting the first and second body portion 10, 20 but the second body portion 20 may in other embodiments simply bear rotatably against a delimiting wall 14 forming an end of the open cavity 11. In the illustrated embodiment, the allowable range for the relative rotation is approximately 100°. In order to further hold the first and second body portion 10, 20 together a retaining element 40 is provided, in the illustrated embodiment a snap ring 40 (shown in FIG. 5).

[0045] In order to limit this relative rotation, a mechanical stop functionality is realized by means of engaging means 13a, 13b on the first body portion 10 adapted to engage corresponding engaging means 23a, 23b comprised by the second body portion 20, shown in cross section in FIG. 2.

[0046] These engaging means are in the present embodiment realized as radial protrusions, or shoulders. In the first body portion 10, two radial protrusions or shoulders 13a, 13b project radially inward and on the second body portion 20 two corresponding radial protrusion 23a, 23b form shoulders projecting radially outwards, such that said first and second shoulder may engage to stop the relative rotation between said first and second body portion, also shown in FIGS. 3 and 4.

[0047] As may be seen for example from FIGS. 3 and 4, the shoulders 13a;13b of the first body portion 10 are formed on an inner cylindrical surface 11a of the open cavity 11 and extend along approximately half the axial length of the open cavity 11 whereas the second body portion comprises a substantially cylindrical end section on which the two shoulder 23a, 23b are arranged. Similarly to the first body portion, the shoulders 23a, 23b extend along the axial length of the cylindrical end portion, corresponding to approximately half the length of the second body portion. Further, each of the shoulder comprise substantially flat engaging surfaces 16, 26 extending in a radial direction, along which the shoulders make contact when engaging.

[0048] The socket unit according to the embodiment may advantageously be used with an electric direct driven tightening tool performing pulsed tightening, i.e. performing a strategy where the motor delivers torque in pulses to the output shaft. More particularly, the tool which constitutes a further aspect of the invention may when having a socket unit according to the invention arranged on the output shaft be operative to perform a method as shown in FIG. 5 comprising the steps of providing a first torque pulse on the output shaft in the tightening direction (S10), rotating the output shaft in a direction opposite to the tightening direction over a predetermined angular interval or time interval such that the first body portion 10 rotates with respect to the second body portion 20 as the second body portion 20 is in engagement with the screw joint (S20) and providing a second torque pulse on the output shaft in the tightening direction such that the first body portion 10 accelerates over the predetermined allowable angular range before hitting the second body portion 20 arranged in engagement with the screw joint (S30) and hence transferring the torque pulse to the joint.

[0049] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. The skilled person understands that many modifications, variations and alterations are conceivable within the scope as defined in the appended claims. Additionally, variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope of the claims.