Ametek NB-3010, Руководство по эксплуатации, Страница: 6 / 24

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3. MECHANICAL DESCRIPTION
3.1 Frame and anvil (See Parts Location Diagram on Page 8)
The hardness tester has a cast iron frame (1). An elevating screw seat (18) is set on
the stage at the front of the frame. The removable anvil (24) is set on the elevating
screw (22), which is fitted precisely into the seat (18). The handwheel (21) elevates the
elevating screw. A steel ball detent (19) is located between handwheel (21) and nut
(20). When the indenter (25) is in contact with the specimen and reaches certain force
as the elevating screw is raised, the handwheel slips which ensure proper force within
an allowable range. Set the ball detent to allow the handwheel to slip at the proper
point. Check the detent in the lowering mode to set the slippage of the elevating
screw.
3.2 Load Lever Mechanism (See Parts Location Diagram on Page 8)
The lever mechanism consists of a large lever (4), small lever (29), hanger (3), and rod
(27), etc.. The arm ratio is 1:12.5 for the large lever, 1:4 for the small lever and overall
ratio is 1:50 for the lever system. The test force is applied to the test piece by the lever
system. On the long arm of large lever is the hanger on which the load weights (7) are
suspended. By the combining weights differently, test loads can be changed. (See
page 6.) The test force is applied when the pneumatic cylinder's piston rod (6) retracts
allowing the weights to descend and apply the load through the fork rocker (5), large
lever (4), small lever (29), rod (27), and main shaft (26).
CAUTION: The load weights should be positioned so that they completely overhang
the edge of the tabletop on which the tester is installed. If this is not done, whenever
the operator fails to raise the indenter to contact against the test specimen, the load
weight assembly can over-travel during the test cycle so that the hanger can come off
the lever and possibly allow the weights to fall.
3.3 Rod Assembly (See Parts Location Diagram on Page 8)
The rod assembly consists of a spring (28), rod (27) , and main shaft (26) etc. While
idle, the spring presses the main shaft in the conical hole and cause the rod to remain
close to the middle knife support of small lever (29) so as to keep the rod in the proper
position. When the test specimen touches the indenter, the main shaft is raised, thus
determining the starting position for the test.
3.4 Pneumatic Tube Assembly (See Parts Location Diagram on Page 8)
The air regulator should be set at 60 psi. The Pneumatic tube assembly consists of the
cylinder mounting bracket (17), the pneumatic cylinder (8), the piston rod (6), the pres-
sure regulator (16), and the fork rocker (5).