Method for tightening a screw connection and screw driving tool
First Claim
1. A method for screwing in and tightening a screw connection (1) to a predetermined tightening level (2), comprising the following steps:
- providing a hand-held screw driving tool (3) with a regulated drive unit (4) or control functionality or both;
performing a screwing-in phase (A);
after said screwing-in phase (A), performing a tightening phase (B-C-D), wherein during said tightening phase (B-C-D), a screw head rests against a bearing surface (6) of the screw connection (1);
increasing a speed (N) of the screw driving tool (3) during the tightening phase (B-C-D) within an acceleration interval (8) to a starting speed (7) for the tightening phase (B-C-D), wherein a quantity corresponding to said acceleration interval is selected from the group consisting of a starting speed, a maximum speed, an instantaneous acceleration, or a limit acceleration, wherein said quantity corresponding to said acceleration interval further is actively changeable, predeterminable, controllable, regulatable, or any combination thereof, and wherein said quantity corresponding to said acceleration interval is independent of individually determined screw joint properties;
decreasing the speed (N) of the screw driving tool (3) within a deceleration interval (9) before achievement or until achievement of the predetermined tightening level (2),wherein the acceleration interval (8) and the deceleration interval (9), taken together, make up a predominant portion of the tightening phase (B-C-D) with regard to a traveled rotation angle (W) of the screw connection (1),and wherein the acceleration interval (8) is shorter than the deceleration interval (9).
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Accused Products
Abstract
Disclosed is a method for screwing in and tightening a screw connection (1) to a predetermined tightened level (2), especially a predetermined torque level (2) or a predetermined pretension level, with the aid of a hand-held screwing tool (3) comprising a regulated drive unit (4) and/or control functionality, particularly an electric nut runner (3). A tightening phase (B-C-D), during which the screw head rests against the supporting surface (6) of the screw connection (1), starts following a screwing phase (A). In order to improve said method, the speed (N) of the screwing tool (3) is increased to an output speed (7) for the tightening phase (B-C-D) within an acceleration time (8) in the tightening phase (B-C-D) and is lowered within a delay time (9) prior to or until reaching the predetermined tightened level (2). The combined acceleration time (8) and delay time (9) represents the predominant part of the entire tightening phase (B-C-D), especially in relation to the traveled angle of twist (W) of the screw connection (1), the acceleration time (8) being shorter than the delay time (9).
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Citations
20 Claims
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1. A method for screwing in and tightening a screw connection (1) to a predetermined tightening level (2), comprising the following steps:
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providing a hand-held screw driving tool (3) with a regulated drive unit (4) or control functionality or both; performing a screwing-in phase (A); after said screwing-in phase (A), performing a tightening phase (B-C-D), wherein during said tightening phase (B-C-D), a screw head rests against a bearing surface (6) of the screw connection (1); increasing a speed (N) of the screw driving tool (3) during the tightening phase (B-C-D) within an acceleration interval (8) to a starting speed (7) for the tightening phase (B-C-D), wherein a quantity corresponding to said acceleration interval is selected from the group consisting of a starting speed, a maximum speed, an instantaneous acceleration, or a limit acceleration, wherein said quantity corresponding to said acceleration interval further is actively changeable, predeterminable, controllable, regulatable, or any combination thereof, and wherein said quantity corresponding to said acceleration interval is independent of individually determined screw joint properties; decreasing the speed (N) of the screw driving tool (3) within a deceleration interval (9) before achievement or until achievement of the predetermined tightening level (2), wherein the acceleration interval (8) and the deceleration interval (9), taken together, make up a predominant portion of the tightening phase (B-C-D) with regard to a traveled rotation angle (W) of the screw connection (1), and wherein the acceleration interval (8) is shorter than the deceleration interval (9). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. An electric screw driving tool (3), comprising:
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a screw driving control unit (5) having a microcontroller, said microcontroller having program code for causing performance of a screwing-in phase (A);
code for causing performance of a tightening phase (B-C-D), wherein during said tightening phase (B-C-D), a screw head rests against a bearing surface (6) of the screw connection (1);
code for causing an increase in a speed (N) of the screw driving tool (3) during the tightening phase (B-C-D) within an acceleration interval (8) to a starting speed (7) for the tightening phase (B-C-D), wherein a quantity corresponding to said acceleration interval is selected from the group consisting of a starting speed, a maximum speed, an instantaneous acceleration, or a limit acceleration, wherein said quantity corresponding to said acceleration interval further is actively changeable, predeterminable, controllable, regulatable, or any combination thereof, and wherein said quantity corresponding to said acceleration interval is independent of individually determined screw joint properties; and
code for causing a decrease in the speed (N) of the screw driving tool (3) within a deceleration interval (9) before achievement or until achievement of the predetermined tightening level (2),wherein the acceleration interval (8) and the deceleration interval (9), taken together, make up a predominant portion of the tightening phase (B-C-D) with regard to a traveled rotation angle (W) of the screw connection (1), and wherein the acceleration interval (8) is shorter than the deceleration interval (9).
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Specification