Rack and Pinion Catalog1 - schlenkent.com

1 Box 8585143 Electric , IL : 708/449-5700800/992-2777 Fax: use of specially adapted thread grinding machines gives our rack a highly accuratehelicoidal tooth profile which provides two distinct advantages - very good pitch accuracyand sufficient tolerance of meshing conditions (within ). This tooth form exhibits a hightolerance to misalignment when meshing with a straight-cut Pinion and is ideal for way this tolerance is derived will be appreciated from the diagram below. Slightmisalignment of the straight tooth Pinion , in terms of deviation from a true right-angle betweenthe axis and the rack in either plane, results merely in a change of position of the contactpoints across the Geometry// Points of contactStandard pressure angel is 20 25 pressure angle available on requestFeatures such as high reliability and repeatability ensure that rack and Pinion systems are thefirst choice for linear and angular measurement applications.

2 By butting lengths of racktogether, extremely long axes can be measured to the highest further information, please call us at 708 ACCURACY GRADESG radeMax. pitch error between any two pointsper 300 mm of rackMax end to end pitch errorup to 300 mm of rack *Adjacent tooth errorPitch Height + + + + + + dimensions in mm*Applies pro rata to lengths > 300 mmApproximately equivalent to grades 9 to Box 8585143 Electric , IL : 708/449-5700800/992-2777 Fax: Assemblies1. Protected rack Channel & Pinion Shaft EncoderTypical System Accuracy mm2. Angular Measuring RackTypical System Accuracy4 seconds of arcfor 1200 mm diameter3. Actuation RackTypical System Accuracy mm per 300 Box 8585143 Electric , IL : 708/449-5700800/992-2777 Fax: have shown that the bolted fixing of any measuring scale onto a mounting surface intro-duces distortion.

3 This results in significant measuring errors, particularly for high Channel has been designed such that the neutral axes in bending intersect at the pitchline of the rack . Even if the channel is bent when installed, the calibrated accuracy will beunaffected. This results in significant savings for machinery builders, because mounting sur-faces need not be perfectly flat (only mm change in accuracy occurs when a 2 m channelis bent by 1 mm).The Neutral Axis ConceptThermal Matching -- Protected rack Channel has a coefficient of thermal expansion equal tothat of cast Domes at the channel ends are within mm of the nominal distance from thepitch line. When placed against a suitable abutment face, butted joint setting is greatly : bidirectional and unidirectional repeatability can rack Channel33333 Usable accuracy - laboratory precision for the shop floor33333 Calibrated to installation- individual sections up to 2m (80 )- minimum of mounting holes- simple pitch line setting33333 Sealed against contaminated environments33333 Unlimited lengths - designed for continuous Box 8585143 Electric , IL : 708/449-5700800/992-2777 Fax.

4 rack ChannelAll dimensions in mm unless otherwise notedStylePRCorURCPart Number CompositionDimensionTypeMC(metric)IC(imp erial)Lengths (1mm)20M(2mm)25M( )10l(1/10 )20l(1/20 )Pressure angle20 degreestandard20 QUALITYT otal Error Bandfor L up to 1000 Total Error Band for Lfrom 1001 to 2000 Max End to End RDimension W1/10 1/20 Box 8585143 Electric , IL : 708/449-5700800/992-2777 Fax: Shaft EncodersAll dimensions in inches unless otherwise statedBEIMODEL H25 EEnvironmental(Manufacturer sCharacteristicsSpecifications)Temp. RangeOperating0 to 70 CStorage-25 C to 90 CHumidityup to 98% RHw/o condensationVibration5-2000 HZ @ 20 GShock50G for 11 msLIFEB earing life at recommended10g revolution meshing forceLight source (Ga Al As diodes)100,000 hrs. COMPATIBLEO ther options availableincluding sinewaves andline drivesCHANNELOPTIONALCOMPLEMENTSPart NumberH25E - SPEH25E - 1 mmNo.

5 OfTeeth2020No. of* **Speed40 in/s1 m/s*5 x INTERPOLATION OPTION ** HIGHER SPEEDS OPTIONALACCURACY .00025 Non-cumulative cyclic Box 8585143 Electric , IL : 708/449-5700800/992-2777 Fax: Measuring RackAll dimensions in mmA unique feature of helicoidalrack is that it provides correctgear action even when mountedon a curved rather than gears can be constructedby clamping a number of racksaround a cylindrical have a narrow face widthand conform elastically todiameters of 570 mm or measuring rack occupies a minimum of axial space allowing rotary tables to be de-signed for greatest stability. All components are serviceable without dismantling the rack circle is made up of either 12 or 24 racks which on assembly are positioned with theirmidpoints at exact angular locations (30 or 15 ). Either a high resolution encoder or an opticalpolygon and autocollimator are suitable references.

6 The major sources of error are the sizetolerances of the seating diameter and its eccentricity:a) The angular measuring error due to seating diameter tolerance is:DDd = where =Subtended angle (radians), D=Diametral error and D=Seating diameter. As eachrack is individually positioned at its midpoint, this error can never accumulate over more thanone rack . Hence the maximum point to point error is at :N2 = where N=Number of racksNDD2d = = arc secondsb) The angular measuring error due to seat eccentricity is:()2 TIRyeccentricteradianssinDe2e = = Example: Seating diameter is1000 mm mm. Numberof racks is 12. The peak topeak error over one rack is seconds ( arc sec-onds, about the midpoint). Box 8585143 Electric , IL : 708/449-5700800/992-2777 Fax: because the rack midpoints are correctly positioned, the error does not accumulatefrom rack to rack :The maximum error occurs on the two racks at 0 and180.

7 The magnitude of this error is:sinradians peak to peakor825000. sin arc secondsExample: For 12 racks on diameter of 1000 mm and a TIR of mm peak to peak error is seconds ( 1/05 arc seconds, about mid point).c) Total AccuracyThe nature of the above errors is such that there is always one rack for which the errors areadditive. Hence the total peak to peak error in the example is arc seconds and is confined toone rack . Total accuracy also includes secondary errors due to installation and Pinion tolerances for a total accuracy specification of 10 arc seconds are presented inthe table below--preferred sizes, all 1 mm pitch:A wide range of other diameters can be : A830-279 Notes:Material: stainless minimum seating diameter should not be less than maximum length of rack not to exceed 600 mm in Pinion carriers are recommended.

8 Anti-backlash pinionscannot be used with angular measuring rack . Pinion carriersmounted onto flex-plates have found to be the best a general rule, rack lengths below 255 mm should use 3 clampsper rack , 255 mm to 375 mm should use 4 clamps per rack , andrack lengths above 375 mm should use 5 or 6 clamps per pitches are available on request. Please contact ourTechnical Sales for further Measuring RackAll dimensions in mmN perpinionrevolution4 4 4 4 4 2 2 2 2 2 1 1 1 1 1 Pinion carrierpart Box 8585143 Electric , IL : 708/449-5700800/992-2777 Fax: Measuring RackAll dimensions in mmMOUNTINGSURFACESA cylindrical mountingseat is required to thediameter and toler-ances stated. Wherevery high accuracy isrequired, we cancompensate for smallpositive diametralerrors by grinding theracks thinner by anappropriate must not be drilled in the racks as this would prevent them from exactly conforming to theseat diameter.

9 The clamp fixing holes should be positioned such that when the table is at itsdatum (zero) position, the Pinion will mesh at themidpoint of one of the must be provided for a wedge or drift to beused in the gap between racks to nudge them intoposition. Procedure:i) Fully tighten clamps on datum rack only. All otherracks should be held in position with only moderatepressure. ii) Set reference zero at datum position oftable and zero the display. iii) Move to 30 or 15 onthe display. iv) Read error from reference. v) Nudgerack until display reading agrees with clamps. Repeat for all NumberR71XR81 XGradeGrades3 and 4 rack Steel416S21 Hardened to 35-40 RcNOTE: Installationcan be madeeasier by invertingthe ofclamps (fromtable). Box 8585143 Electric , IL : 708/449-5700800/992-2777 Fax: CarriersAll dimensions in mmStandard Quality AQ12.

10 Higher qualities available on Pinion carriers are radial loading on Pinion is NumberAnti-backlashAPC1MX20-APC2MX20-APC 25MX20-APC31X20-APC62X20-Part 1/20 Number of TeethMinMax8540323265 PreferredSizePlain2010. 2510. 2010. 2020A/B4625202037 Plain2010101020 MATERIALS: Pinion and Bearings-Stainless Box 8585143 Electric , IL : 708/449-5700800/992-2777 Fax: AssembliesAll dimensions in transducers up to 67 mm diameter, use FP21 For transducers larger than 67 mm diameter or Pinion carriers user FP10 Adaptor PlatesThese adaptor plates mounttransducers onto aFlex-plate where aPinion Carrier is not - a Pinion shaft encoderScrews & Clamps suppliedMaterial: Aluminum AlloyTransducer typeBEI EncoderH25 EBEI EncoderH25 GBlank for customerto finishAdaptor PlatePart NumberB830-312-1B830-318B830-315 Box 8585143 Electric , IL : 708/449-5700800/992-2777 Fax: dimensions in mmBy sprig loading the Pinion into mesh on both flanks of the teeth, complete backlash elimination isachieved.