FORD SL4-1988 SAFETY CHAINS《安全链》.pdf

1、 Manufacturing StandardsFord Motor Company198807 SAFETY CHAINS SL4Engineering Standards & Printed copies are uncontrolled.Systems Engineering (ESSE) Page 1 of 31. SCOPE: This standard states the requirements for safety chain design,specifications, uses and inspection.2. APPLICATION: Safety chains as

2、 covered by this standard include alloccasions where secondary support is considered essential in case theprime means of attachment fail. Items such as trolley hung weldingtransformers are further attached by safety chains.3. TYPES OF SAFETY CHAINS: This standard in no way restricts design orapplica

3、tion of safety chains, provided material and attachments are inaccord with material specifications and are approved by the Safety Unitof using locations.4. SPECIFICATIONS: The standard material for safety chains shall be grade70 chain, that will develop a tensile strength of 101,500 lbs/in2(71,364,6

4、50 kgs/m2), with a minimum elongation during the break test of15%.This standard does not apply to the use of special purpose safety chainfrom stainless steel, monel metal, bronze or other material for specialapplication where low carbon steel would be adversely affected bycorrosive fumes or substanc

5、es. This would constitute a specialapplication and approval must be obtained from using plants Safety Unit.5. PRECAUTION: Safety chains, when in either safe or prime supportposition, shall be so placed that they will never be able to complete anelectric circuit.6. LENGTH: The length of safety chains

6、 should be kept to a minimum to suitcase of installation and to limit “fall distance“ of unit being supportedto minimize impact loads.7. FITTINGS AND FASTENERS: All members attached to safety chain ends, toserve as fittings or closure fasteners, must be capable of carrying theequivalent of the rated

7、 chain capacity. All fittings and fasteners mustbe purchased under the same material specifications so that they will beconsistent with the same tensile strength as the chain.8. CHAIN STRENGTH: The following tabulation shows the safe load limit to beapplied to a chain supporting a static weight and

8、the safe load limitwhen used as a safety chain.G70 Chain: Trade Size Load Limit1/4 in (6.4mm) Up to 3,150 lbs (1,430 kg)3/8 in (9.5mm) 3,150 to 6,600 lbs (3,000 kg)1/2 in (12.7mm) 6,601 to 11,300 lbs (5,130 kg)Manufacturing StandardsFord Motor Company198807 SAFETY CHAINS SL4Engineering Standards & P

9、rinted copies are uncontrolled.Systems Engineering (ESSE) Page 2 of 39. SUGGESTED APPROVED TYPE OF FASTENERS:See Figure A.NOTE: Open end repair links or cold shut attachments are not acceptable.10. CHAIN AND ANCHOR SHACKLES: The following tabulation shows therecommended minimum trade size shackle ap

10、plied to respective chain size.Chain Shackle ShackleTrade Size Trade Size Pin Diameter1/4 in (6.4mm) 5/16 in (7.9mm) 3/8 in (9.5mm)3/8 in (9.5mm) 7/16 in (11.1mm) 1/2 in (12.7mm)1/2 in (12.7mm) 5/8 in (15.9mm) 3/4 in (19.1mm)11. INSPECTION: Inspect safety chains before each usage on those chains tha

11、tserve a multiple purpose.On permanently attached chains inspection frequency shall be at regularintervals based on severity of usage and potential damage. Minimumfrequency at least every six months on permanent type installations inaddition to above, every time “prime unit is serviced or relocated.

12、“11.1 METHOD OF INSPECTION (PERMANENT TYPE INSTALLATION):.1 Observe and retighten any loose fasteners.2 Observe condition of chain and fasteners regarding indicationsof cracks or other failures on a regular inspection schedule.3 Visually check conditions of member supporting safety chain.4 Check for

13、 corrosion or atmospheric damage (possible groundingdamage in case of welding transformer safety chain).11.2 METHOD OF INSPECTION (MULTIPLE PURPOSE TYPE):.1 Check chain for cracks.2 Excessive wear or handling damage.3 Fitting and fasteners.4 Do not use improvised connectors to attach.11.3 Report all

14、 defects to responsible Safety personnel.11.4 Safety representative shall authorize continued use or immediatelyrequest replacement.Manufacturing StandardsFord Motor Company198807 SAFETY CHAINS SL4Engineering Standards & Printed copies are uncontrolled.Systems Engineering (ESSE) Page 3 of 3FIGURE ASUGGESTED APPROVED TYPES OF FASTENERS