DE20116080U1 - Manually operated carrier arm for screwdriver has measurement system to ensure correct location - Google Patents

Abstract

The manual screwdriver (6) is retained in a holder (5) that is supported at the end of a parallelogram of links (4) to ensure the screwdriver is always vertical. The linkage connects with a pivot mounted arm (3) on a stand. Built into the mechanisms are position measuring devices (7-9) that provide absolute position measurement of the screwdriver.

Description

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FUCHS, Reinhard

Hand-operated support arm system for holding hand screwdrivers

Description

In the field of handling and production technology, support arms, parallel arms, spring balancers or other holding devices are used to

Hand screwdriver is hung or mounted. The idea behind this is that the torque to be tightened is absorbed on the one hand and that the screwdriver can be positioned in a way that is suitable for the job on the other.

For some screw connections, a specific screwing sequence must be followed, e.g. tightening crosswise. It is also important that no screw connection is forgotten. It is also important to ensure that all washers and snap rings are screwed on.

Up to now, the screwing sequence, the number of screws and the screw control have been checked separately using a wide variety of devices. With an EC screwdriver, the number of screw connections and an exact screwing result are guaranteed. The screwing is carried out with a tested torque using a strain gauge sensor and with angle precision using a rotary encoder.

One supplier is known to have an XY system with which positions can be approached and controlled in the manner described above. The Z axis is not implemented. Other suppliers try to use bulky
Special machines called XYZ arms to specify the position. All systems that can be easily changed in position must be

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The start must be set to a machine zero point. The other systems are rigid with fixed initiators in the position.

The task is to create a hand-operated support arm system for holding hand-held screwdrivers with which exact positioning in all three planes is possible, which also detects missing washers, snap rings or other shims and which can be used for simple electric or pneumatic shut-off screwdrivers, as well as EC screw systems.

According to the invention, a hand-operated support arm system with at least two arms for holding hand-held screwdrivers with means for storing positions in at least one axis, characterized in that means for detecting positions consist of at least one encoder of an absolute value system, wherein at least two positions of the hand-held screwdriver relative to a screw to be screwed in can be detected by means of control electronics and stored in these. According to a preferred embodiment of the invention, a first position is a start position of the hand-held screwdriver and a second position is a switch-off position of the hand-held screwdriver after proper screwing. The start position and/or the switch-off position is preferably designed as an adjustment window to compensate for tolerances.

Preferably, the switch-off position is detected according to a tested torque.

According to a preferred embodiment of the invention, means are provided for detecting positions from sensors of an absolute value system for at least three axes of the support arm system, wherein the detected positions can be stored in the control electronics. Preferably, the sensor(s) are SSI sensors.

The hand-operated support arm system according to the invention consists, according to the accompanying drawings, of a frame 1 with a fastening 2 for a first arm 3 pivotable in a plane S, to which a parallel arm 4 is connected,

which is arranged to pivot in a parallel plane S', but which is articulated on the first arm 3 in such a way that it can also pivot perpendicular to the planes S and S'. At the free end of the parallel arm 4 there is a holder 5 for a hand screwdriver 6. 13-bit SSI encoders 7, 8 are installed in the X-axis between the attachment 2 and the arm 3 and in the Y-axis between the arm 3 and the parallel arm. A 15-bit SSI encoder 9 is installed in the Z-axis, around which the parallel arm rotates for vertical pivoting. The evaluation electronics are housed in a housing 10 with just three buttons 14 and a key switch 11. The various operating states are displayed using three LEDs 12 and a four-line LCD display. The control electronics are freely programmable.

The position is entered in two steps:

- Start position: screw is not yet screwed in and is directly above the screw position;

- Shut-off position: screw is properly tightened.

For example, the screw is lightly screwed on by hand or brought into the screwing position using a magnetic bit or vacuum sleeve. The screwdriver is connected to the screw and the start position is saved in the control electronics by pressing a button (start window). The screw is then correctly screwed in with all the spacers. After the torque switch-off of the screwdriver has taken place, the position reached is also saved (torque display window). This ensures that the screwdriver only turns in the respective start position and that a 10-screw connection is signaled by the control electronics if the torque switch-off point matches. If the screwdriver is moved upwards again during the screwing process, a signal is emitted that indicates a NIO screw connection. This also happens if the switch-off torque does not occur in the correct position in the torque switch-off window. The accuracy of the position is specified by the electronics. The size of the setting window determines how far the screwdriver position can be from the start window. This is necessary if the torque switch-off point is not in the correct position.

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to compensate for the looseness in the bit, the bit holder, the screws and the workpiece tolerances. The more precise the device and the workpiece are, the narrower the setting window can be. This combination of start window position and shut-off position gives an exact statement as to whether the right screw has been screwed in the right place with all the necessary shims. The screwing process is interrupted after the screwing time has elapsed using an additionally activatable screwing time. Torn threads or screws that are too long are detected.

Claims (6)

1. Hand-operated support arm system with at least two arms ( 3 , 4 ) for holding hand screwdrivers ( 6 ) with means for storing positions in at least one axis, characterized in that
that means for detecting positions consist of at least one sensor ( 7 , 8 , 9 ) of an absolute value system,
wherein at least two positions of the hand screwdriver ( 6 ) relative to a screw to be screwed in can be detected by means of control electronics and stored therein. 2. Hand-operated support arm system according to claim 1, characterized in that a first position is a start position of the hand-held screwdriver ( 6 ) and that a second position is a switch-off position of the hand-held screwdriver after proper screwing. 3. Hand-operated support arm system according to claim 2, characterized in that the switch-off position is detected according to a tested torque. 4. Hand-operated support arm system according to claim 2 or 3, characterized in that the start position and/or the switch-off position is designed as an adjustment window to compensate for tolerances. 5. Hand-operated support arm system according to one of the preceding claims, characterized in that means for detecting positions from sensors of an absolute value system for at least three axes of the support arm system are present, wherein the detected positions can be stored in the control electronics. 6. Hand-operated support arm system according to one of the preceding claims, characterized in that the sensor or sensors are SSI sensors.