1、AEROSPACE RECOMMENDEDPRACTICEARP493REV.AIssued 1964-06Revised 2001-10Reaffirmed 2011-08Superseding ARP493Knobs, Control Aircraft, Recommended DesignFOREWORDChanges in this revision are format/editorial only.1. SCOPE:This recommended practice is intended to recommend the basic shapes and dimensions f
2、or knobs used in aircraft. Two basic types of knobs, the bar shape and the round shape, are described, as well as several widely used variations of these two basic shapes.2. PURPOSE:The purpose of this document is to recommend shapes and sizes of knobs which will guide the design of these components
3、 toward eventual uniformity.3. REQUIREMENTS:3.1 Materials:It is recommended that materials conform to requirements of the latest issue of MIL-K-25049 and meet the environmental conditions stated therein.3.2 Metals:It is recommended that metals used in knobs shall be of the corrosion-resistant type o
4、r be suitably treated to resist corrosion in salt spray or atmospheric conditions.SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and sui
5、tability for any particular use, including any patent infringement arising therefrom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Cop
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8、AE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP493 Revision A- 2 -3.3 Set Screws:Two locking-type set screws should be employed to hold the knob to the shaft. The set screws should be the “hex socket he
9、ad“ type, as shown on drawing AN565. Set screws should be in accordance with SAE standards. Where applicable, set screws should be 90 to 135 apart, located on either side of the center line of the flat of the shaft. This is to push the flat of the shaft against the flat of the insert.3.3.1 A minimum
10、 of three threads in metal should be provided for the set screws.3.3.2 Where molded plastic knobs with metal inserts are used, set screw holes in the plastic should be counterbored to a size to clear the outside diameter of the set screw.3.4 Torque:The knob, when mounted on a shaft, should withstand
11、 a torque of 25 inch-pounds in either direction.3.5 All plastic knobs should have metal inserts molded or cast in the plastic to fit around shafts.3.6 All shaft holes in knobs should have a flat on one side.4. SKIRTS - KNOBS:4.1 Fastening Skirt to Knob:It is recommended that, where a skirt is a sepa
12、rate part, it should be fastened to the knob by a positive means of fastening such as spinning insert over the skirt and 1/16 inch diameter pin through the skirt into the knob, so as not to allow movement of either skirt or knob with respect to each other. Another suitable method, where space allows
13、, is to screw skirt to the knob, using flat head screws. In this case, skirt screw holes are to be countersunk.4.2 Runout:T.I.R. on skirts after assembly should be held to 0.032.4.3 Wobble:T.I.R. on knobs including wobble should be held to 0.020.Copyright SAE International Provided by IHS under lice
14、nse with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP493 Revision A- 3 -5. REFERENCE SPECIFICATIONS:MIL-P-7788A - Plate, Plastic LightingMIL-K-25049 - Knobs, Control, Equipment AircraftMIL-S-7742 - Screw Threads, Standard, Optimum Selected Series: Gen
15、 Spec forMIL-C-18012 - Control, Configuration and Markings (for Plastic Lighting Plates, Control Panels and Placards)6. ILLUMINATION:All knobs with requirements for illumination shall be made in accordance with the latest issue of MIL-K-25049.PREPARED UNDER THE JURISDICTION OFSAE SUBCOMMITTEE A-20,
16、FLIGHT CREW STATION,OF COMMITTEE A-20, AIRCRAFT LIGHTINGCopyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP493 Revision A- 4 -FIGURE 1Copyright SAE International Provided by IHS under license wit
17、h SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP493 Revision A- 5 -FIGURE 2Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP493 Revision A- 6 -FIG
18、URE 3Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP493 Revision A- 7 -FIGURE 4Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking pe
19、rmitted without license from IHS-,-,-SAE ARP493 Revision A- 8 -FIGURE 5Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP493 Revision A- 9 -FIGURE 6Copyright SAE International Provided by IHS un
20、der license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP493 Revision A- 10 -FIGURE 7Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP493 Re
21、vision A- 11 -FIGURE 8Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP493 Revision A- 12 -FIGURE 9Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproductio
22、n or networking permitted without license from IHS-,-,-SAE ARP493 Revision A- 13 -FIGURE 10Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP493 Revision A- 14 -FIGURE 11Copyright SAE Internatio
23、nal Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP493 Revision A- 15 -FIGURE 12Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license fro
24、m IHS-,-,-SAE ARP493 Revision A- 16 -FIGURE 13Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP493 Revision A- 17 -FIGURE 14Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
