DE3926611A1

DE3926611A1 - Electronic run=up speed limitation esp. for drill - introducing brief delay with low-speed drive for centring purposes in prepn. for full-speed drilling

Info

Publication number: DE3926611A1
Application number: DE19893926611
Authority: DE
Inventors: Gustav Flier
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-08-11
Filing date: 1989-08-11
Publication date: 1991-02-14

Abstract

The motor (M) of an electric drill is supplied with current from two speed control circuits (1,2). One circuit (1) is operative immediately to run-up the motor for a drilling speed. of only a few rev/min during a delay (TV) of a few seconds until the other circuit (2) is actiavated. This allows the drill bit to be centred precisely for a preliminary drilling before the main hole is drilled at normal speed. ADVANTAGE - Easily mass-produced device reduces risk of tearing and blockage, and allows accurate centring for all kinds of holes.

Description

Die Erfindung soll trotz allgemein eingeführter elektro nischer Drehzahlregelung die Anlaufdrehzahl über eine Zeitspanne von einigen Sekunden auf wenige UpM be grenzen, um das "Einreißen" beim Aufbohren mit der damit verbundenen Gefahr des "aus der Hand schlagens" der Bohr maschine weitgehend zu vermeiden und jeden Bohransatz als Vor- oder Nachbohrung zielführend bei kleiner Drehzahl auszuführen.The invention is intended despite the generally introduced electro nical speed control the starting speed a period of a few seconds to a few rpm limit to the "tearing" when boring with the associated risk of "knocking out of hand" the Bohr machine to be largely avoided and every drilling approach as Pre-drilling or post-drilling is effective at low speed to execute.

Bei Nachbohrungen kommt ein größerer Bohrerdurchmesser zum Einsatz, der insbesondere bei einer handgeführten Bohr maschine immer zum Einreißen neigt, womit meist die Kont rolle über die Bohrmaschine verloren geht, dabei durch festeren Handgriff die Drehzahlregelung voll durch gezogen wird, d. h. der Bohrer zum blockieren führt und Verletzungsgefahr auftritt.With re-drilling there is a larger drill diameter used, especially in a hand-held drill machine tends to tear, with which the cont roll over the drill is lost, thereby firmer handle fully through the speed control is pulled, d. H. the drill leads to blocking and there is a risk of injury.

Die Erfindung hat zum Ziel, diese Gefahr zu vermeiden so wie beim Vorbohren, ohne eine zusätzliche Regelungs-Hand habung, zentriergenau arbeiten zu können.The aim of the invention is to avoid this danger as with pre-drilling, without an additional control hand have the ability to work with centering accuracy.

Erfindungsgemäß wird dies dadurch erreicht, daß nach Abb. 1 dem elektronischen Drehzahl-Regelkreis (1) ein zweiter Drehzahl-Regelkreis (2) vorgeschaltet ist, der über eine Verzögerungszeit von einigen Sekunden eine nicht zu beeinflussende niedrige Drehzahl von einigen UpM vorgibt und erst nach Ablauf dieser Verzögerungszeit T_V den zweiten, bedienbaren Drehzahl-Regelkreis (2) aktiv werden läßt; oder nach Abb. 2, daß dem Regelkreis (2) ein Verzögerungsglied (3) mit der Verzögerungszeit T_V integriert ist, das dem Regelkreis (2) über die Zeit T_V eine unbeeinflußbare niedere Anfangsdrehzahl-Ansteuerung auferlegt. Wegen der Vielzahl der Drehzahl-Regelmöglich keiten kann auf Schaltungsdetails nicht eingegangen werden.According to the invention, this is achieved in that, according to Fig. 1, the electronic speed control circuit ( 1 ) is preceded by a second speed control circuit ( 2 ) which, over a delay time of a few seconds, specifies a low speed of a few rpm which cannot be influenced and only after Expiry of this delay time T _V allows the second, operable speed control circuit ( 2 ) to become active; or according to Fig. 2, that the control circuit ( 2 ) has a delay element ( 3 ) integrated with the delay time T _V , which imposes an uncontrollable low starting speed control on the control circuit ( 2 ) over the time T _V. Due to the large number of speed control options, circuit details cannot be discussed.

Claims

1. Electronic start-up speed limitation , in particular for drilling machines, according to the invention characterized in that a speed control circuit at the beginning of each work cycle over a time T _V of a few seconds customer sets the speed uninfluenced to a few rpm and only then does the operable speed control active can be.

2. Electronic starting speed limitation, in particular for drilling machines, according to claim 1 according to the invention characterized in that according to Fig. 1, the operable speed control circuit ( 1 ) is preceded by a second speed control circuit ( 2 ) which has a delay time T _V of a low speed of a few rpm, which cannot be influenced, for a few seconds and only releases the speed control loop ( 1 ) after T _{V has} elapsed.

3. Electronic starting speed limitation, especially for drilling machines, according to claim 1 according to the invention characterized in that according to Fig. 2, the operable speed control circuit ( 1 ), a delay element ( 3 ) with the delay time T _{V is} integrated, the control circuit ( 2 ) an uncontrollable low starting speed control is imposed over the time T _V.

4. Electronic starting speed limitation, especially for drills, according to claim 1 to 3, fiction, according to characterized in that the delay time T _V can be increased by an accessible controller.