Browse Prior Art Database

Screwdriving Process Control Using Driver RPM Instrumentation

IP.com Disclosure Number: IPCOM000122254D
Original Publication Date: 1991-Nov-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 3 page(s) / 73K

Publishing Venue

IBM

Related People

Mason, JE: AUTHOR [+4]

Abstract

In any automated screwdriving process it is important to detect when a screw jams so that corrective action can take place. In this article we propose the use of an encoder attached to the rotating portion of an electric screwdriver. Fig. 1 shows how a standard angle encoder was attached to a motor shaft of a standard (HIOS) electric screwdriver along with Fig. 2 which shows the details of that attachment. Note that this attachment was made to an existing driver without changing the size of the driver.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 93% of the total text.

Screwdriving Process Control Using Driver RPM Instrumentation

      In any automated screwdriving process it is important to
detect when a screw jams so that corrective action can take place.
In this article we propose the use of an encoder attached to the
rotating portion of an electric screwdriver. Fig. 1 shows how a
standard angle encoder was attached to a motor shaft of a standard
(HIOS) electric screwdriver along with Fig. 2 which shows the details
of that attachment. Note that this attachment was made to an existing
driver without changing the size of the driver.

      A general layout of how the sensor would be used is shown in
the form of a block diagram given in Fig. 3.  The main objective is
for the encoder to measure the number of turns which the screw makes
after contact with the work piece is made.  This number is then
compared to the number of turns required to complete the screwdriving
process based on the pitch and length of the screw.  Furthermore, the
signal from the encoder could be differentiated to measure driver
RPM.  Then, if the driver stops rotating before the expected number
of rotations was completed, it would signal that the screw had jammed
and corrective action could be taken (e.g., the driver reverses to
back out the screw or the operator is called).  A simple block
diagram of this process is shown in Fig. 4.

      As previously mentioned, counting the number of turns and
comparing that to the required number is contingent o...