Patent ID: 9062495
Filing Date: 2015-06-23
Classification: B25D,E21B

Abstract:
1. A drilling machine with a normal impact position, in which the components of the drilling machine are in a position for impact against rock, and with an idle impact position, in which idle impacts are impacts against air, which drilling machine comprises the following components: a shank adapter; a damping piston with a forward end surface; a stop end surface for the damping piston; a rotation chuck bushing with a forward end surface; a stop end surface for the rotation chuck bushing; an impact piston with a brake land with a forward end surface; and a brake chamber for braking the impact speed of the impact piston in the event of idle impacts, which brake chamber has a rear edge; wherein the damping piston has an idle impact stroke length defined as a distance between the stop end surface of the damping piston and a position of the front end surface of the damping piston at the normal impact position of the drilling machine; the rotation chuck bushing has an idle impact stroke length defined as a distance between the stop end surface of the rotation chuck bushing and a position of the forward end surface of the rotation chuck bushing at the normal impact position of the drilling machine; the actual idle impact stroke length of the damping piston is the shorter of the idle impact stroke length of the damping piston and the idle impact stroke length of the rotation chuck bushing; the impact piston has an idle impact braking length defined as a distance between the rear edge of the brake chamber and a position of the forward end surface of the brake land at the normal impact position of the drilling machine; and the actual idle impact stroke length of the damping piston is greater than the idle impact braking length of the impact piston.