SAE AIR 4905-1996 Wheel Chocks《止轮块》.pdf

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1、400 Commonwealth Drive, Warrendale, PA 15096-0001SAE 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 entirelyvoluntary, and its applicability and suitability for any particular use, in

2、cluding 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.Copyright 2002 Society of Automotive Engi

3、neers, Inc.All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE.TO PLACE A DOCUMENT ORDER: Tel: 877-606-

4、7323 (inside USA and Canada)Tel: 724-776-4970 (outside USA)Fax: 724-776-0790Email: custsvcsae.orgSAE WEB ADDRESS: http:/www.sae.orgAEROSPACE INFORMATION REPORTAIR4905Issued 1996-07Reaffirmed 2002-06Wheel ChocksFOREWORDThe use of wheel chocks is the most common means to restrain an aircraft while it

5、is parked. Wheel chocks may also be used as a back-up to aircraft parking brakes. Wheel chocks are used to restrain an aircraft from movement due to ground slope or normal wind velocities without engine power. During certain ground operations, chocks are unable to provide adequate restraint. Such is

6、 the case during engine run-ups or high wind conditions. Unsafe ground handling of aircraft and associated activities have resulted in serious personnel injuries, flight delays, and in some cases substantial damage to the aircraft. This SAE Aerospace Information Report (AIR) discusses a number of fa

7、ctors that affect wheel chock design and use.1. SCOPE:The purpose of this document is to present general considerations for the design and use of aircraft wheel chocks. The design and use of aircraft wheel chocks is a good deal more complicated than it may appear at first glance.2. REFERENCES:There

8、are no referenced publications specified herein.3. DESIGN CONSIDERATIONS:Many decisions must be made when selecting the proper chock design depending on the application and the environment in which it is used. Factors that must be taken into account in the design of aircraft chocks include:a. Materi

9、al: Performance degradation and physical deterioration due to environmental factors such as temperature, sunlight, moisture, sand and dust, fungus, snow and ice, salt, fuel, oil, hydraulic fluid, and solvents must be considered.Copyright SAE International Provided by IHS under license with SAENot fo

10、r ResaleNo reproduction or networking permitted without license from IHS-,-SAE AIR4905 - 2 -3. (Continued):b. Width: Determined by the width of the aircraft tire(s) to be restrained and whether it will be used to restrain more than one wheel on an axle, or axle pair (i.e., if fore and aft on same bo

11、gie, different axles).c. Height: Sized to adequately restrain the aircraft tire. Height of the wheel chock is primarily a function of the aircraft tire size. Typical chock heights range from 6 to 12 in (15.2 to 30.5 cm).d. Weight: Should be light enough for ease of manual installation, yet heavy eno

12、ugh to preclude the possibility of blowing away due to jet blast or high wind conditions. Unsecured wheel chocks on the ramp pose a safety hazard to personnel and aircraft.e. Shape: Typically have a triangular cross section, although polygonal and square cross sections are also available. An approxi

13、mate 45 chock angle at the point at which the tire is contacted, provides maximum holding ability. A more gradual angle will allow the tire to run up the chock and pinch it. A steeper angle decreases the downward pressure on the chock, thus allowing it to slip more easily. Some chock designs incorpo

14、rate a curved shape to provide maximum contact area with the aircraft tire. A laterally grooved surface will improve the gripping performance in adverse weather conditions.Appendix A illustrates typical aircraft wheel chock cross sections.f. Strength: Material used to manufacture chock must be able

15、to hold a fully loaded and fueled aircraft and not crush under the weight of the aircraft.g. The durability of the chock to withstand operational usage including shock and vibration.h. The applicability of the wheel chock to a wide variety of aircraft. Special purpose chocks should be identified wit

16、h aircraft type(s) for which they are intended to be used.i. Safety related aspects including the possibility of the chock being inadvertently blown away by jet blast or in high wind conditions.j. Brightly colored wheel chocks provide maximum visibility on the ramp. Operators may wish to consider th

17、e addition of reflective material to chocks in order to provide visibility at night.k. The ability to easily and safely carry, install, and remove the wheel chocks. A rope or handle attached to the chock may facilitate this requirement.Copyright SAE International Provided by IHS under license with S

18、AENot for ResaleNo reproduction or networking permitted without license from IHS-,-SAE AIR4905 - 3 -4. EVALUATION OF EXISTING DESIGNS:4.1 Welded Metal Cages:a. Moderate weight and very durable.b. Disadvantage is that sharp metal edges may damage the aircraft tire.c. More likely to cause damage to th

19、e airplane if flipped up during an incident.d. The welded metal cage is more prone to skid and can cause a spark.e. Highly resistant to oils, fuels, and chemicals.f. Excellent holding capability on ice.g. Will not rot or crack.h. Must be painted or have reflective material added to improve visibilit

20、y. Some maintenance required.4.2 High Density Rubber Chocks:a. Superior chocking on dry or wet concrete or asphalt because of the high coefficient of friction and large area in contact with the ramp.b. This type of chock can be heavy. A typical extruded rubber chock 6 in (15.2 cm) high can weigh 8 t

21、o 10 lb/ft (11.9 to 14.9 kg/m), with lengths available up to 6 ft (1.83 m). The same size molded rubber chock may weigh up to 12 lb/ft (17.9 kg/m).c. Poor holding capability on snow or ice unless equipped with removable cleats or spikes.d. Highly resistant to oils, fuels, chemicals, and corrosion.e.

22、 Indefinite lifetime (nonrecurring cost).f. Will not break or crack.g. Commonly molded only in black rubber. Chock may need to be painted or have reflective material added to improve visibility. Some maintenance required.Copyright SAE International Provided by IHS under license with SAENot for Resal

23、eNo reproduction or networking permitted without license from IHS-,-SAE AIR4905 - 4 -4.3 Urethane Chocks:a. Have similar characteristics to rubber chocks, but can be made lighter by means of using a lighter filler or have hollow or foam filled centers.b. Highly resistant to oils, fuels, chemicals, c

24、orrosion, and abrasion.c. Indefinite lifetime (nonrecurring cost).d. Can be molded in bright colors to provide maximum visibility. Never needs painting. No maintenance required.e. Poor holding capability on snow or ice unless equipped with removable cleats, spikes, or a metal edge. Excellent holding

25、 characteristics on dry concrete or asphalt.4.4 Wooden Chocks:a. Most economical chock - typically made from No. 1 common fir lumber.b. Average life of 15 to 20 months (recurring cost).c. Excellent holding capability on dry or wet concrete or asphalt.d. Prone to splintering (may be a safety issue).

26、Also prone to rotting, breaking, and cracking; not weather resistant. Often need painting to maintain maximum visibility. Maintenance required.4.5 Cleats/Spikes:a. Can be bolted onto wooden, rubber, or urethane chocks to improve holding capability on ice or hard packed snow.b. Usually made of metal.

27、 Can be as simple as a sharpened bolt protruding through the bottom of the chock.c. Personnel should exercise caution when handling to ensure safety.Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-SAE

28、AIR4905 - 5 -5. CONSIDERATIONS FOR USE:a. Select wheel chocks appropriate to the tire size and size of the aircraft.b. Wheel chocks should be placed snugly and squarely against the tire tread area except during airplane loading/fueling. As the airplane is loaded, the tires deflect and may pinch the

29、chock, making it difficult to remove. Placing the chock a slight distance in front of and at the rear of, the tire will prevent the tire from settling on top of the chocks.c. Too much space between the tire(s) and chock(s) may allow the airplane to gain enough momentum to allow the tire(s) to roll o

30、ver the chock(s). The number of and placement of chocks should be in accordance with the airframe manufacturers recommendations.Chocks should not be left on the ramps or taxiways where they can be a hazard to taxied or towed aircraft or vehicles.d. Bright colored chocks enhance visibility to aircraf

31、t and ramp personnel.e. Always use wheel chocks in pairs (fore and aft) and on firm surfaces. Chock pairs should be tied together to prevent movement out of position which could happen if an aircraft is bouncing during windy conditions.f. Aircraft parking brake should be set before chocks are remove

32、d.g. Airline personnel should refer to the airframe manufacturers maintenance manual procedures for restraining an aircraft during engine run-up. Wheel chocks are not intended to restrain the aircraft during an engine run-up. They are used as a precautionary measure as a backup to the aircraft parki

33、ng brake, both before and after the engine run-up.h. Increased caution must be exercised when chocking aircraft wheels if adverse weather or ramp conditions exist or are forecast.i. Always remove wheel chocks before attempting to move aircraft. Do not drive over wheel chocks.j. When preparing for gr

34、ound movement, remove chocks only after attachment of tow vehicle and/or a brake rider is in the aircraft.PREPARED BY SAE SUBCOMMITTEE AGE-2C,VEHICLE MAINTENANCE AND AIRCRAFT SERVICINGOF COMMITTEE AGE-2,AIR CARGO AND AIRCRAFT GROUND EQUIPMENT AND SYSTEMSCopyright SAE International Provided by IHS un

35、der license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-SAE AIR4905 - 6 -APPENDIX ATYPICAL AIRCRAFT WHEEL CHOCK CROSS SECTIONSFIGURE A1Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-