| 摘要 |
A ball bearing hammer actuator comprises a hammer lever which is connected at the one end to the hammer and which is connected at the other end to a shoe which is slidable in relation to guide surface having a U-shaped cross section. The guide surface is provided for by a portion of the frame which has a generally U-shaped cross section. The shoe of the ball bearing hammer actuator includes a body having a generally rectangular shape which is designed to fit within the U-shaped guide. The shoe fits within the guide with a small clearance, the clearance allowing for use of ball bearings. Two edges of the body of the shoes include elongated recesses. The recesses receive a plurality of bearing balls therein. The bearing balls protrude from the bottom of the shoe and the sides of the shoe. The bearing balls are in contact with the walls and the floor of the U-shaped guide. A spring mechanism urges the shoe upwardly.
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