Analysis of Vehicle Stability When Using Two-Post Above-Ground Automotive Lifts: Support Pad Slippage
Abstract
:1. Introduction
1.1. Vehicles Falling off Two-Post Above-Ground Automotive Lifts
- Do not exceed the lift’s capacity.
- Ensure the lift area for the vehicle is clear of people and objects.
- Position the vehicle according to its center of gravity (CG).
- Choose the support pads and check their condition.
- Identify the lift points under the vehicle and check condition (no damage, antirust substance, ice or dirt, etc.).
- Lock the swing arms.
- Check the vehicle’s stability.
- Stay at the controls while lifting.
- Make sure that the fall-arrest system is working properly.
- Use jack stands when removing heavy components from the vehicle.
2. Methodology
2.1. Global Approach
2.2. Consultation of Key Players
2.3. Experimental Design
2.3.1. Experimental Conditions
2.3.2. Controlled Factors
Support Pad Type (Pa1, Pa2)
Smear on Support Pads (S0, S1)
Support Pad Position (P1, P2)
Arm Locking (L0, L1)
External Force Type (F1, F2)
2.3.3. Measurements
2.3.4. Planning of Tests, Protocol and Statistical Analysis
- The vehicle was positioned properly in relation to the lift columns, respecting a previously determined mark on the ground.
- The support pads were placed at the recommended lifting points, always in the same orientation in relation to the x and y axes.
- The vehicle was raised to head height in order to make the marks on the support pads and the vehicle frame, and then lowered back down to approximately 20 cm from the ground for the test.
- Forces were applied to the vehicle and recorded.
- After checking the displacement of the support pads, the vehicle was raised to head height and secured with 4 jack stands.
- The displacement measurements along the x and y axes were taken by a team member and compiled in a spreadsheet by another team member.
- The jack stands were removed and the vehicle was lifted down to the ground.
2.3.5. Additional Testing
3. Results
3.1. Key Players: Support Pad and Related Issues
3.2. Experimental Design
3.2.1. Support Pad Slippage Measured
3.2.2. Statistical Analysis
4. Discussion
4.1. Controlled Factors’ Influence on the Slippage
4.1.1. Support Pad Type
4.1.2. Smear on Support Pads
4.1.3. Support Pad Position
4.1.4. Arm Locking
4.1.5. Type of Force
4.1.6. Additional Testing
4.2. A Multifactorial Problem
- Lifting point of the vehicle positioned on the edge of the support pad: This situation causes two phenomenons: (a) A slight slippage of the support pad can induce the fall of the vehicle, especially for pads without stops. There is no safety margin, as slippages were measured during the tests in many configurations (up to 53% of the pad half-width). (b) It maximizes the play in the cantilevered support pad and causes the pad to be inclined, thus inducing horizontal forces.
- Support pad type and external forces: support pad type and external force type are the ones that have the greatest influence on support pad slippage according to the ANOVA. However, more data are needed on support pad and the match with lifting points in real conditions.
- Support pad with very little or no charge: a lift arm with almost no charge is more easily moveable, especially if some play exists in the lift arm locking system [3]. Hence, the question relative to the arm locking system is not only a question of maximum force and resistance, but also a question of allowable play when the arm is locked. According to Woody and MacDonald [18], the design of some arm locking systems should be retrofitted.
4.3. Experimental Limitations
5. Conclusions
- The initial placement of the support pad is a major safety measure, as support pad slippage can go up to 53% of the pad half-width. Moreover, many test configurations led to support pad slippage. A bad initial pad placement (pad edge) could lead to a contact loss between the vehicle and support pad, and ultimately a fall of the vehicle.
- Support pad slippage is much lower for the soft rubber pads. This coating gives better results than their steel counterparts in these experimental conditions (i.e., type of vehicle and configuration of the lifting points).
- The external force type has a significant impact on the slippage: lateral impacts imparted with a sledgehammer generated greater displacements than vertical pushes in the trunk.
- Finally, lifting the vehicle down to the ground and lifting it again without readjusting the position of the support pads when the contact was lost is potentially dangerous, as it caused displacements of up to 32 mm in the testing with the pick-up truck. This is already a non-recommended practice, but it can happen sometimes inadvertently.
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
- Société de l’Assurance Automobile du Québec (SAAQ). Nombre de Véhicules en Circulation Selon Le Type D’utilisation, Le Type de Véhicule Et L’âge Du Véhicule, Québec Et Régions Administratives [Number of Vehicles in Circulation by Type of Use, Type of Vehicle and Age of Vehicle, Québec and Administrative Regions]; Gouvernement du Québec: Quebec, QC, Canada, 2021. [Google Scholar]
- American National Standard Institute (ANSI); Automotive Lift Institute (ALI). Standard for Automotive Lifts—Safety Requirements for Operation, Inspection and Maintenance (ALOIM); ALI: Cortland, NY, USA, 2008. [Google Scholar]
- Burlet-Vienney, D.; Galy, B.; Kusson Bertrand, K. Analysis of Vehicle Stability When Using Two-Post Above-Ground Automotive Lifts: Distribution of Forces in Arms. Saf. Sci. 2021, 134, 105042. [Google Scholar] [CrossRef]
- Centre de Documentation. Available online: https://www.centredoc.cnesst.gouv.qc.ca/in/fr (accessed on 20 January 2022).
- American National Standard Institute (ANSI); Automotive Lift Institute (ALI). Standard for Automotive Lifts—Safety Requirements for Installation and Service (ALIS); ALI: Cortland, NY, USA, 2009. [Google Scholar]
- American National Standard Institute (ANSI); Automotive Lift Institute (ALI). Standard for Automotive Lifts—Safety Requirements for Construction, Testing and Validation (ALCTV); ALI: Cortland, NY, USA, 2017. [Google Scholar]
- BS EN 1493:2010; Vehicle Lifts. British Standards Institution (BSI): London, UK, 2010.
- BS 7980:2013+A1:2012; Vehicle Lifts—Installation, Maintenance, Thorough Examination and Safe Use—Code of Practice. British Standards Institution (BSI): London, UK, 2014.
- AS/NZS 2550.9:1996; Standards Australia and Standards New Zealand (Standards AS/NZ). Cranes—Safe Use. Part 9: Vehicle Hoists. Standards Australia: Homebush, Australia, 1996.
- AS/NZS 1418.9:1996; Standards Australia, Standards New Zealand (Standards AS/NZ). Cranes (Including Hoists and Winches) Part 9: Vehicle Hoists. Standards Australia: Homebush, Australia, 1996.
- Auto Prévention. Le Travail Sous Le Véhicule. In Le Levage De Véhicules Sur Pont Élévateur À Deux Colonnes [Work under the Vehicle. Vehicle Lifting with Two-Post above Ground Lift]; Auto Prévention: Brossard, QC, Canada, 2014. [Google Scholar]
- Auto Prévention. L’entretien Préventif Des Ponts Élévateurs [Preventive Maintenance of Automotive Lifts]; Auto Prévention: Brossard, QC, Canada, 2019. [Google Scholar]
- Heath, R. Don’t Be an Accident Statistic—Lift It Right; ALI: Cortland, NY, USA, 2013. [Google Scholar]
- Valladeau, A.S.; Lupin, H. Réparation Et Entretien Des Véhicules Automobiles Légers (ED6282) [Repair and Maintenance of Light Motor Vehicles]; INRS: Paris, France, 2017. [Google Scholar]
- Eberhard, J.; Green, P. The Development and Testing of Warnings for Automotive Lifts; The University of Michigan Transportation Research Institute: Ann Arbor, MI, USA, 1989. [Google Scholar]
- Williams, M.; Green, P.; Paelke, G. Further Development of Warnings for Automotive Lifts; The University of Michigan Transportation Research Institute: Ann Arbor, MI, USA, 1991. [Google Scholar]
- Barnett, R.L.; Glauber, J.B. Automotive Lifts—Unrestrained vs. Restrained Swing Arms. Saf. Brief 2009, 29, 373–387. [Google Scholar]
- Woody, P.; McDonald, A. Assessment of the Arm Locking Systems of Two-Post Vehicle Lifts (RR1030); Health and Safety Laboratory: Buxton, UK, 2015. [Google Scholar]
- Yin, R.K. Case Study Research: Design and Methods, 4th ed.; SAGE Publications: Thousand Oaks, CA, USA, 2009. [Google Scholar]
- St-Vincent, M.; Vézina, N.; Bellemare, M.; Denis, D.; Ledoux, É.; Imbeau, D. L’intervention En Ergonomie [The Intervention in Ergonomics]; IRSST/Éditions Multi Mondes: Montreal, QC, Canada, 2011. [Google Scholar]
- Theureau, J. Le Cours D’action: Analyse Sémio-Logique [The Course of Action: Semio-Logical Analysis]; Peter Lang: Berne, Switzerland, 1992. [Google Scholar]
- Bricki, N.; Green, J. A Guide to Using Qualitative Research Methodology; London School of Hygiene and Tropical Medicine: London, UK, 2007. [Google Scholar]
- Patton, M.Q. Qualitative Research. In Encyclopedia of Statistics in Behavioral Science; Everitt, B.S., Howell, D.C., Eds.; Wiley: Hoboken, NJ, USA, 2005. [Google Scholar]
- Palinkas, L.A.; Horwitz, S.M.; Green, C.A.; Wisdom, J.P.; Duan, N.; Hoagwood, K. Purposeful sampling for qualitative data collection and analysis in mixed method implementation research. Adm. Policy Ment. Health 2015, 42, 533–544. [Google Scholar] [CrossRef] [PubMed] [Green Version]
- Carignan, M. Optimiser La Performance Par La Planification D’expériences (DOE) [Optimizing Performance by Experimental Plans]; ÉTS Formation/Différence: Montreal, QC, Canada, 2018. [Google Scholar]
- Dagnelie, P. Principes D’expérimentation: Planification des Expériences et Analyse de Leurs Résultats [Experimental principles: Planning of Experiments and Analysis of Their Results]; Presses Agronomiques: Gembloux, France, 2012. [Google Scholar]
- Linder, R. Les Plans D’expériences, Un Outil Indispensable À L’expérimentateur [Experimental Plans, an Essential Tool for the Experimenter]; Presses de l’École Nationale des Ponts et Chaussées: Paris, France, 2005. [Google Scholar]
- Alexis, J.; Alexis, P. Pratique industrielle des plans d’expériences. In La Qualité À Moindre Coût: La Méthode Tagushi [Industrial Practice of Experimental Plans. Quality at a Lower Cost: The Tagushi Method]; AFNOR: Paris, France, 1999. [Google Scholar]
- Automotive Lift Institute (ALI). Vehicle Lifting Points for Frame Engaging Lifts; Model Years (1995–2019); ALI: Cortland, NY, USA, 2019. [Google Scholar]
- Kletz, T.A. Inherently safer design—Its scope and future. Process Saf. Environ. Prot. 2003, 81, 401–405. [Google Scholar] [CrossRef]
Themes | Examples of Information Collected |
---|---|
Automotive lift market | Lift models available on the market (brands, types, construction standards, new vs. used products), most popular, advantages, buyers and users, responsibilities and obligations of manufacturers and suppliers |
Buying process | Formulation of requests/needs by the buying garages (visit of suppliers), variables to define the needs and characteristics of the lift (capacity, space, type of work to be confucted on the vehicle), place of occupational health and safety for the buyers, examples of specifications, guarantees offered |
Implementation in garages Training and information on the use of lifts | Modalities/procedures for the installation of lifts in the garages, physical and organizational implementation plan developed by the buyers (people authorized to use it, lifts dedicated to a type of task) Training provided: when (hiring, purchase of a new lift, refurbishment), who (training center, supplier, fellow mechanic) and to whom, contents/methods (duration, theory/practice), information documents given to owners of new lifts |
Use | Are recommendations/specifications for lift use followed? Main risks, consideration of risks for users, challenges/difficulties in using lifts (vehicle model, type of tasks to be conducted, user experience) |
Vehicle falls | Description of vehicle falls, circumstances, contributing factors to falls, means of assessing vehicle stability, resources for assessing stability and risk |
Inspection and maintenance | Daily and periodic inspections/maintenance, criteria/tools provided (inspection/maintenance guide), skills required (responsibility mechanic, owner, specialized technician, engineer), condition of lifts in garages, main problems/interventions/exemptions related to lift maintenance or repair, lift life span |
Reducing the risks associated with falling vehicles | Existing technical or organizational means to limit risks, available resources (experts, organizations, information), solutions to reduce risks (developments, necessary interventions) |
Controlled Factors | Level/Code | Description | Illustrations | |
---|---|---|---|---|
Support pad type (Pa) | Pa1: Rubber | Square support pad with soft rubber cover | Pa1 | Pa2 |
Pa2: Metal | Foldable steel support pad | |||
Support pad smear (S) | S0: Clean | Support pads and lifting points cleaned | S1 | |
S1: Smeared | Support pads covered with multipurpose grease | |||
Support pad position (P) | P1: Centered | Lifting point centered on the support pad | P1 | P2 |
P2: Off centered | Lifting point off centered on the support pad | |||
Arm locking (L) | L0: Unlocked | 4 locking devices not used | L0 | L1 |
L1: Locked | 4 locking devices in use | |||
External force type (F) | F1: Lateral impact | Sledgehammer impacts on the rear right wheel | F1 | F2 |
F2: Vertical force | Vertical forces exerted by hand to the trunk |
Support Pad Type (Pa) Pa1 (Rubber); Pa2 (Metal) | Support Pad Smear (S) S0 (Clean); S1 (Smeared) | Support Pad Position (P) P1 (Centered); P2 (Off Centered) | Arm Locking (L) L0 (Unlocked); L1 (Locked) External Force Type (F) F1 (lateral); F2 (Vertical) | |
---|---|---|---|---|
Pa1 | S0 | P1 | L1-F2; L0-F2; L0-F1; L1-F1 | Original |
Pa1 | S0 | P2 | L1-F1; L0-F1; L0-F2; L1-F2 | |
Pa1 | S1 | P1 | L1-F2; L0-F2; L0-F1; L1-F1 | |
Pa1 | S1 | P2 | L1-F1; L0-F1; L0-F2; L1-F2 | |
Pa1 | S1 | P1 | L1-F2; L0-F2; L0-F1; L1-F1 | Replicate |
Pa1 | S1 | P2 | L1-F1; L0-F1; L0-F2; L1-F2 | |
Pa1 | S0 | P1 | L1-F2; L0-F2; L0-F1; L1-F1 | |
Pa1 | S0 | P2 | L1-F1; L0-F1; L0-F2; L1-F2 | |
Pa2 | S0 | P1 | L1-F2; L0-F2; L0-F1; L1-F1 | Original |
Pa2 | S0 | P2 | L1-F1; L0-F1; L0-F2; L1-F2 | |
Pa2 | S1 | P1 | L1-F2; L0-F2; L0-F1; L1-F1 | |
Pa2 | S1 | P2 | L1-F1; L0-F1; L0-F2; L1-F2 | |
Pa2 | S1 | P1 | L1-F2; L0-F2; L0-F1; L1-F1 | Replicate |
Pa2 | S1 | P2 | L1-F1; L0-F1; L0-F2; L1-F2 | |
Pa2 | S0 | P1 | L1-F2; L0-F2; L0-F1; L1-F1 | |
Pa2 | S0 | P2 | L1-F1; L0-F1; L0-F2; L1-F2 |
Thematic | Test |
---|---|
Other support pad slippage tests | Support pad slippage: compact vehicle, trunk loaded (216 kg). Tested configurations: Pa2S0P1L0F1 and Pa2S0P2L0F2 Support pad slippage: pick-up (weight: 2436 kg; wheel base: 3531 mm; track width: 1700 mm) and Pa2 (metal). Tested configurations: Pa2S0P1L0(F1/F2) with and without load in the trunk (216 kg). Support pad slippage: front/rear external force type on the pick-up, Pa2 support pads folded in the same way and locked arms. Tested configuration: Pa2S0P1L1 |
Non-compliant work practice | Support pad displacement following the lifting down of the vehicle to the ground (support pads not in contact with the lifting points anymore) and lift off of the vehicle without readjusting the support pad position. Tested configurations with replicas:
|
Concerns | Explanation |
---|---|
Compliance with recommended lifting points | Mechanics may have difficulties to reach the lifting point recommended by the manufacturer because of (i) the physical limits of the lifts (e.g., out of reach with telescopic arms) (Figure 7), (ii) the vehicle specifications (e.g., space between the ground and frame of the vehicle, plastic parts, damaged lifting points, rust), and (iii) the mismatch between the type of pads available and the characteristics of the lifting point (e.g., foldable steel support pads only offer three heights). |
Support pad suitability | There is a great variability of vehicles (e.g., size, characteristics of lifting points) and support pads (e.g., materials, surface pattern, size, height adjustments and clearances) (Table 2). Each support pad has its own specifications and mechanical behavior. A support pad type is sometimes not the most suitable for a situation (e.g., pad with stops and a large flat lifting point). It is sometimes difficult to have the best “support pad-lifting point” match and it is not always possible to change the type of support pad on a lift. |
Support pad positionning | Support pads should be positioned with the pad axis centered with the lifting point of the vehicle (Table 2). This type of positioning requires the mechanic to bend under the vehicle and to thoroughly adjust the support pad position. Some key players are concerned about the fact that this adjustment is not conducted properly each time (e.g., because of knee pain, lack of time, poor housekeeping/snow, by habits). Moreover, the height of the pad is not always adjusted, which can cause a pad to not support as much weight as it should. |
Contaminant agents | The presence of contaminant agents on the support pads or lifting points of the vehicle was mentioned as a risk factor during consultation (Table 2). |
Arm locking system | During lifting of the vehicle, arm locking systems must be active. However, these devices demand a careful maintenance to be fully functional. Mechanics should verify that the arms are locked during lifting. Some key players expressed their concerns on this point. |
Work on vehicles | When working on vehicles, mechanics can apply significant forces with tools to remove mechanical parts. These forces exerted (e.g., changing tires) can generate vehicle movement. Other more complex work such as removing the transmission or the engine can change the position of the vehicle’s CG. |
Controlled Factor | Pad A (mm) | % of Half-Width A | Pad B (mm) | % of Half-Width B | Pad C (mm) | % of Half-Width C | Pad D (mm) | % of Half-Width D |
---|---|---|---|---|---|---|---|---|
F1 (lateral) | 0.3 | 0.4% | 0.5 | 0.8% | 0.1 | 0.2% | 0.0 | 0.0% |
F2 (vertical) | 0.6 | 1.0% | 0.3 | 0.5% | 0.3 | 0.5% | 0.0 | 0.0% |
L0 (unlocked) | 0.4 | 0.7% | 0.4 | 0.7% | 0.3 | 0.6% | 0.0 | 0.0% |
L1 (locked) | 0.4 | 0.7% | 0.3 | 0.5% | 0.1 | 0.1% | 0.0 | 0.0% |
P1 (centered) | 0.3 | 0.6% | 0.1 | 0.2% | 0.1 | 0.2% | 0.0 | 0.0% |
P2 (off-centered) | 0.5 | 0.8% | 0.6 | 1.1% | 0.3 | 0.5% | 0.0 | 0.0% |
S0 (clean) | 0.6 | 1.0% | 0.3 | 0.5% | 0.3 | 0.5% | 0.0 | 0.0% |
S1 (smear) | 0.3 | 0.4% | 0.4 | 0.7% | 0.1 | 0.2% | 0.0 | 0.0% |
Average | 0.4 | 0.7% | 0.4 | 0.6% | 0.2 | 0.3% | 0.0 | 0.0% |
Controlled Factor | Pad A (mm) | % of Half-Width A | Pad B (mm) | % of Half-Width B | Pad C (mm) | % of Half-Width C | Pad D (mm) | % of Half-Width D |
---|---|---|---|---|---|---|---|---|
F1 (lateral) | 2.0 | 3.6% | 3.2 | 5.9% | 14.7 | 26.8% | 13.6 | 24.8% |
F2 (vertical) | 1.2 | 2.1% | 1.0 | 1.8% | 2.5 | 4.5% | 1.1 | 1.9% |
L0 (unlocked) | 1.9 | 3.4% | 2.7 | 4.9% | 9.3 | 17.0% | 7.7 | 13.9% |
L1 (locked) | 1.3 | 2.3% | 1.5 | 2.8% | 7.8 | 14.3% | 7.0 | 12.8% |
P1 (centered) | 1.0 | 1.8% | 2.3 | 4.2% | 9.4 | 17.1% | 9.6 | 17.4% |
P2 (off-centered) | 2.1 | 3.9% | 1.9 | 3.5% | 7.8 | 14.1% | 5.1 | 9.3% |
S0 (clean) | 1.4 | 2.6% | 2.2 | 4.1% | 6.6 | 12.0% | 4.7 | 8.6% |
S1 (smear) | 1.7 | 3.1% | 2.0 | 3.6% | 10.6 | 19.2% | 10.0 | 18.1% |
Average | 1.6 | 2.9% | 2.1 | 3.8% | 8.6 | 15.6% | 7.4 | 13.4% |
Source | Degree of Freedom | Sum of the Squares | Mean Square | F-Value |
---|---|---|---|---|
Model | 7 | 13,637.135 | 1948.16 | 45.9785 |
Error | 56 | 2372.784 | 42.37 | Prob. > F |
Corrected total | 63 | 16,009.919 | <0.001 |
Source | Sum of the Squares | F-Value | Prob. > F |
---|---|---|---|
Support pad Pa | 5566.60 | 131.38 | 0.00000 |
Support pad Pa × External force F | 3172.98 | 74.89 | 0.00000 |
External force F | 3058.24 | 72.18 | 0.00000 |
Smear S × External force F | 728.61 | 17.20 | 0.00012 |
Support pad position P × External force F | 432.59 | 10.21 | 0.00230 |
Support pad Pa × Smear S | 365.35 | 8.62 | 0.00481 |
Smear S | 312.75 | 7.38 | 0.00875 |
Mean Slippage (mm) | Pad A | Pad B | Pad C | Pad D | |
---|---|---|---|---|---|
V1S0P1 (compact) | Pa1 (rubber) | 2 | 2 | 1 | 2 |
Pa2 (metal) | 1 | 2 | 2 | 0 | |
L0 (unlocked) | 1 | 3 | 2 | 1 | |
L1 (locked) | 2 | 2 | 1 | 1 | |
V2Pa2S0P1L0 (pick-up) | 16 | 16 | 19 | 23 |
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. |
© 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
Share and Cite
Burlet-Vienney, D.; Galy, B.; Cusson Bertrand, K.; Beaugrand, S.; Gonella, M.; Ledoux, É. Analysis of Vehicle Stability When Using Two-Post Above-Ground Automotive Lifts: Support Pad Slippage. Safety 2022, 8, 58. https://doi.org/10.3390/safety8030058
Burlet-Vienney D, Galy B, Cusson Bertrand K, Beaugrand S, Gonella M, Ledoux É. Analysis of Vehicle Stability When Using Two-Post Above-Ground Automotive Lifts: Support Pad Slippage. Safety. 2022; 8(3):58. https://doi.org/10.3390/safety8030058
Chicago/Turabian StyleBurlet-Vienney, Damien, Bertrand Galy, Kariane Cusson Bertrand, Sylvie Beaugrand, Maud Gonella, and Élise Ledoux. 2022. "Analysis of Vehicle Stability When Using Two-Post Above-Ground Automotive Lifts: Support Pad Slippage" Safety 8, no. 3: 58. https://doi.org/10.3390/safety8030058
APA StyleBurlet-Vienney, D., Galy, B., Cusson Bertrand, K., Beaugrand, S., Gonella, M., & Ledoux, É. (2022). Analysis of Vehicle Stability When Using Two-Post Above-Ground Automotive Lifts: Support Pad Slippage. Safety, 8(3), 58. https://doi.org/10.3390/safety8030058