1、Designation: F 1887 09An American National StandardStandard Test Method forMeasuring the Coefficient of Restitution (COR) of Baseballsand Softballs1This standard is issued under the fixed designation F 1887; the number immediately following the designation indicates the year oforiginal adoption or,
2、in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This procedure is intended to standardize a method ofmeasuring the coefficient of
3、 restitution (COR) of baseballs andsoftballs.1.2 This procedure is established to provide a single, repeat-able, and uniform test method.1.3 This procedure is for a ball that is intended for use in thegame of baseball or softball.1.4 The test method is based on ball speed measurementsbefore and afte
4、r impact with either of two test surfaces: woodor metal.1.5 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresp
5、onsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Terminology2.1 Definitions of Terms Specific to This Standard:2.1.1 baseball and softball, nany ball defined by the rulesfor the ga
6、me of baseball or softball.2.1.2 coeffcient of restitution (COR), na numerical valuedetermined by the exit speed of the ball after contact divided bythe incoming speed of the ball before contact with a massive,rigid, flat wall of either wood or metal.3. Summary of Test Method3.1 Method AThe strike p
7、late is a rigid metal surface, andball speed is measured before and after impact with the strikeplate.3.2 Method BThe strike plate is a rigid wood surface, andball speed is measured before and after impact with the strikeplate.4. Significance and Use4.1 The ball coefficient of restitution is a ball
8、dynamicproperty of relative velocity change caused by impact with arigid wall.4.2 This test method is suitable for obtaining data inresearch and development, quality control, and classifyingballs by liveliness.4.3 Sports associations can use coefficient of restitutionstandards in specifications for
9、official baseballs and softballs.4.4 This same test procedure can be utilized at impactspeeds other then that prescribed in this procedure and so notedin any reported test results.5. Apparatus5.1 Strike Plate, Method A:5.1.1 Material, 5.08-cm (2-in.) thick steel.5.1.2 Size, 61 by 61 cm (24 by 24 in.
10、).5.1.3 Mounting, secured flush to a massive rigid wall ofcinder block or concrete, minimally 20.3-cm (8-in.) thick, andbolted at all four corners sufficiently secure to prevent move-ment during ball impact.5.2 Strike Plate, Method B:5.2.1 Material, 10.2-cm (4-in.) thick northern white ashwood with
11、moisture content between 10 and 15 % with a flatsmooth surface.5.2.2 Same as 5.1.2.5.2.3 Same as 5.1.3.5.3 Ball Throwing Device2Aball throwing device capableof delivering the ball through the electronic speed monitor at1This test method is under the jurisdiction of ASTM Committee F08 on SportsEquipm
12、ent and Facilities and is the direct responsibility of Subcommittee F08.26 onBaseball and Softball Equipment.Current edition approved June 1, 2009. Published June 2009. Originallyapproved in 1998. Last previous edition approved in 2002 as F 1887 02.2The sole source of supply of the apparatus (ATEC,
13、Model “Casey” orequivalent, or a suitable air cannon device) known to the committee at this time isAthletic Training Equipment Co., Sparks, NV. If you are aware of alternativesuppliers, please provide this information to ASTM International Headquarters.Your comments will receive careful consideratio
14、n at a meeting of the responsibletechnical committee,1which you may attend.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.26.82 m/s (60 mph) with a maximum tolerance of 60.30 m/s.The machine should be calibrated using the electronic
15、 speedmonitor.5.4 Electronic Speed Monitors3An electronic ball speedmeasuring system consisting of two vertical light screensmounted 30.48 cm (12 in.) apart with a tolerance of 60.32 cm,and a photoelectric sensor located at each screen that triggersa timing device on ball passage to measure the time
16、 for the ballto traverse the distance between the two vertical planes beforeand after impact with the strike plate. Resolution shall be60.03 m/s.5.5 Ball Trajectory TargetA lightweight target with a30.48-cm (12-in.) diameter circular opening positioned at thesecond light screen and centered on the b
17、all line of travelbetween the throwing device and the center of the strike plate.6. Preparation of Apparatus6.1 Mount the strike plate on a rigid wall such that thecenter is approximately 1.22 cm (4 ft) from the floor. Tightenall mounting bolts before each test. Torque to 81.35 N-m (60ft-lb) min.6.2
18、 Position the first speed monitor (light screen) 30.48 60.32 cm (12 6 0.125 in.) from the strike plate (see Fig. 1).6.3 Position the second speed monitor (light screen) 30.486 0.079 cm (12 6 0.312 in.) from the first speed monitor.6.4 Position the ball throwing device such that the ballimpacts the s
19、trike plate within 15.24 cm (6 in.) of the centerand on rebound, passes through the 30.48 cm (12 in.) targetmounted at the second light screen.7. Conditioning7.1 Ball Conditioning and Test Room Conditions:7.1.1 Test balls shall be stored in an environmentallycontrolled space for at least 14 days imm
20、ediately beforetesting.7.1.2 Temperature is to be maintained at 72 6 4F (22 62C).7.1.3 Relative humidity is to be maintained between 40 and60 %.7.1.4 Temperature and relative humidity are to be measuredand recorded hourly within 60.5F (60.3C) and 62%RHover conditioning and test duration.8. Procedure
21、8.1 The ball throwing device is set to deliver the ball at26.82 6 0.305 m/s (60 mph). All shots above or below thistolerance range will not be used.8.2 Each ball is shot at the strike plate a minimum of sixtimes to a maximum of 12 times. A minimum 30-s rest periodis required between each shot.8.3 On
22、ly those speed readings for impacts falling within the6-in. target at the strike plate, within the 12-in. target at thesecond speed monitor, and thrown within the prescribed speedrange will be used in the calculation of COR.8.4 The average of the six acceptable COR values for eachball is used to det
23、ermine the ball COR.8.4.1 Formulae:COR 5 Vb/Va 516FVb1Va11Vb2Va21Vb3Va31Vb4Va41Vb5Va51Vb6Va6G(1)where:Va = incoming speed, andVb = exit speed.9. Report9.1 Report the following information:9.1.1 Name of the test facility and test operator,9.1.2 Test date,9.1.3 Hourly measurements of test conditions,
24、including:3The sole source of supply of the apparatus (Oehler Research Chronograph,Model 35x2, or equivalent; Oehler Research Skyscreens, Model 55, or equivalent)known to the committee at this time is Oehler Research Inc., Austin, TX. If you areaware of alternative suppliers, please provide this inf
25、ormation to ASTM Interna-tional Headquarters. Your comments will receive careful consideration at a meetingof the responsible technical committee,1which you may attend.FIG. 1 Test ApparatusF18870929.1.3.1 Relative humidity and temperature of the ball con-ditioning and test room environments,9.1.3.2
26、Number of hours ball was in conditioning environ-ment.9.1.4 Test equipment used for this test method,9.1.5 Test ball information, model, weight tested, and anyother pertinent data such as condition of the ball,9.1.6 For each event impact (including invalid impacts), ballinbound speed, rebound speed,
27、9.1.7 Average ball COR in accordance with Section 8 of thisstandard,9.1.8 Any and all unique observations, including but notexclusively, any damage to the ball, and9.1.9 Calibration certificate numbers for measurement de-vices and velocity timers.10. Precision and Bias10.1 Precision and bias evaluat
28、ions have not been con-ducted for these test methods. When such data are available, aprecision and bias section will be added.10.2 Report COR values to three digits (that is, x.xxx).11. Keywords11.1 ball liveliness; ball resilience; baseball; coefficient ofrestitution; softballASTM International tak
29、es no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own re
30、sponsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addres
31、sed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at th
32、e address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).F1887093
