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ASME PALD 5c-1990 — Mechanical Screw Jacks Safety Standard Addenda (c)
📦 ASME/ANSI PALD-5c-1990 is the third and final Addenda to the ASME/ANSI PALD-5-1987 Mechanical Screw Jacks volume. It was approved by ANSI on October 25, 1990, and issued on November 30, 1990. Changes are marked by the margin note (c), while (a) and (b) identify the two earlier Addenda. With its revisions to definitions, scope, wholesale renumbering of the test paragraphs, an errata correction, and the addition of metric conversion guidance, this Addenda closes out the 1987 edition, leaving the screw jack requirements complete and aligned with the international system of units.
💡 The new Appendix B (Metric Units Conversion Table) marks this volume’s international outlook: U.S. Customary parameters such as rated capacity and lifting height can be converted to metric values, helping manufacturers and international purchasers share a common understanding.
1. Summary of Changes 📌
| Page | Location | Change |
|---|---|---|
| vii | Contents | Updated to reflect Addenda (c) |
| 1–2 | Introduction | (1) Second paragraph of General revised; (2) Section I revised |
| 5 | Paras. 1.1, 1.2 Scope/Purpose | Revised |
| 5 | Para. 1.4 Illustrations | Revised |
| 5 | Section 2 — definition of “functional damage” | Revised |
| 5 | Para. 3.3 (design) | Revised |
| 6 | Para. 4.1 (capacity marking) | Revised |
| 6–7 | Para. 5.1 (proof tests) | Revised and renumbered: 5.1.1→5.1.3, 5.1.2→5.1.1, 5.1.2.1→5.1.1.1, 5.1.2.2→5.1.1.2, 5.1.3→5.1.2 |
| 7–8 | Section 6 (product instructions and warnings) | Subparagraphs (c) and (h) and the last paragraph revised |
| 8 | Para. 7.1.3(c) | Corrected by Errata |
| 10 | Appendix B — Metric Units Conversion Table | Added |
⚠️ Note the wholesale renumbering of the test paragraphs: the former 5.1.2 (including 5.1.2.1/5.1.2.2) moved forward to 5.1.1, the former 5.1.1 moved back to 5.1.3, and the former 5.1.3 became 5.1.2. Always confirm that a cited test paragraph comes from the post-1990 current text.
2. Definition and Scope Revisions 🔬
The revised “functional damage” definition sharpens the acceptance boundary: any permanent deformation of the structure, saddle, or lifting mechanism that causes loss of load or failure to meet the design qualification limits. The scope revisions to paras. 1.1–1.4 tighten the description of the covered equipment — self-contained mechanical screw jacks for lifting one wheel clear of the ground for emergency tire changing on vehicles up to 11,000 lb (4,990 kg) GVW — and the updated illustration 1.4 shows the typical screw jack construction (base, threaded column, crank mechanism, saddle) more clearly.
🚨 Functional damage is the scrapping criterion: any permanent deformation — thread peening or collapse, bending, saddle deformation, or base cracks — means the jack must be scrapped and not used again. Direct visual inspection plus periodic measurement are the most effective ways to catch early damage.
3. Test Paragraph Renumbering and Errata Correction 📋
In Section 5, the proof test paragraphs were reorganized wholesale: the centered proof load test, the off-center load test, and their subparagraphs were restructured into the 5.1.1/5.1.2 framework, so load application method, load position, and acceptance criteria are more systematic. The revisions to subparagraphs (c) and (h) and the last paragraph of Section 6 complete the elements of the warning label; one line of para. 7.1.3(c) was corrected by Errata, removing ambiguity in the use and inspection provisions. For users, all revisions are incorporated into the 1987 edition as replacement pages; the final text is base pages + (a) + (b) + (c).
4. Impact on Manufacturers and Users 📊
- 🔍 Test documentation: update test plans, report templates, and acceptance citations to the renumbered paras. 5.1.1/5.1.2.
- 🔧 Marking verification: after the revision of para. 4.1, rated capacity marking is more explicit; check nameplates and warning labels.
- 📐 Metric conversion: use Appendix B to convert U.S. Customary values to metric units, unifying procurement and inspection documents.
- 📋 Final version: 5c is the final Addenda; subsequent full editions of the Standard supersede the addenda mechanism.
5. Frequently Asked Questions ❓
❓ Q: 5c is the “final Addenda” — what comes next?
A: 5c is the last Addenda for the 1987 edition. As planned in the Foreword, the next full edition supersedes the 1987 text. Until then, manufacturing and inspection follow the consolidated text of “base pages + (a) + (b) + (c).”
A: 5c is the last Addenda for the 1987 edition. As planned in the Foreword, the next full edition supersedes the 1987 text. Until then, manufacturing and inspection follow the consolidated text of “base pages + (a) + (b) + (c).”
🔍 Q: Why were the test paragraphs renumbered?
A: The committee reorganized the proof test framework, renumbering the centered/off-center tests and their subparagraphs in logical order (e.g., 5.1.2→5.1.1) so the “test-acceptance” structure is clearer. Test plans citing old numbers must be updated.
A: The committee reorganized the proof test framework, renumbering the centered/off-center tests and their subparagraphs in logical order (e.g., 5.1.2→5.1.1) so the “test-acceptance” structure is clearer. Test plans citing old numbers must be updated.
❓ Q: What is the purpose of Appendix B?
A: Appendix B provides conversions between U.S. Customary and metric units (e.g., lb→kg, in→mm), helping manufacturers and users on the SI system correctly interpret rated capacity, lift heights, and other parameters without conversion errors.
A: Appendix B provides conversions between U.S. Customary and metric units (e.g., lb→kg, in→mm), helping manufacturers and users on the SI system correctly interpret rated capacity, lift heights, and other parameters without conversion errors.
❓ Q: Does the errata correction affect product conformity?
A: The errata corrects the wording of para. 7.1.3(c) to remove ambiguity; it is a textual correction that does not change the technical substance of the requirement. Inspection documents should still be updated to the current text.
A: The errata corrects the wording of para. 7.1.3(c) to remove ambiguity; it is a textual correction that does not change the technical substance of the requirement. Inspection documents should still be updated to the current text.
