LEADSCREWS AND LINEAR RAILS 2 Leadscrews & Linear Rails

Introduction

Huco has chosen to offer Kerk Leadscrews because they are designed specifically for precision motion control applications. The screw thread form is unique to Kerk and has been created for maximum life, quiet operation and repeatable accuracy.

Positional bi-directional repeatability is achieved within 0.0013 mm (0.0005î) and standard lead accuracy is better than 0.0006 mm/mm. Lead accuracies are available to 0.0001 mm/mm with individual screw mapping (laser interferometer verification) optional.

A number of unique, patented, anti-backlash nut options are available to suit a variety of load conditions. Kerk nuts are characterised by low drag torque, low wear and high axial stiffness.

Kerk ScrewRailsTM are a patented innovation in linear motion, combining both drive and support / guidance functions in a single, compact, coaxial component.

The ScrewRail’s unique design eliminates the need for any external rail to screw alignment, giving savings in space as well as cost over typical two-rail systems.

Where external rail support is required Kerk Linear Rails are designed to provide low cost, low friction and long life in a variety of motion control applications. Linear rails are available in burnished or TFE coated stainless steel.

The Kerk Spline Shaft system has been designed for light load applications, again where low cost, low friction and long life are needed. These assemblies consist of light weight, aluminium splined shafts treated with Kerkís proprietary low friction TFE coating, mated with graphite and PTFE filled thermoplastic bushings. The bushings are supplied with integral brass collars to enable various mounting options without distorting the nut.

Tel: +44 (0) 1992 501900 Leadscrews 3

Axial take-up mechanism

The standard method for taking up backlash is to ∆ 1 LOAD bias two nut halves axially using some type of compliant spring. Wavy washer, compression spring, (L) NUT HALF NUT HALF rubber washer, etc.)

The unit is very stiff in the direction in which the nut half is loaded against the flank of the screw thread. However, in the direction away from the screw thread, the nut is only as axially stiff as the amount This gap (∆1 + ∆2) is now the amount of backlash of preload which the spring exerts. which has developed in the unit. This backlash can be removed by replacing the stiff spacer with a SPRING PRELOAD new spacer equal to (L+∆1 + ∆2). This process, although effective, would be extremely costly and NUT HALF NUT HALF difficult to implement on a continuous basis.

What is needed then, is a stiff spacer which will

For example, if the the maximum axial load to which SPRING FORCE the system is subjected is 20kg., the amount of NUT HALF LOAD AGAINST spring preload must be equal to, or greater than, SCREW FLANK 20kg. in order to maintain intimate screw/nut contact. The problems arising from preloading in this manner are increased torque and nut wear.

Obviously, the higher the load at the screw/nut continually expand to accommodate the wear interface, the higher the required torque to drive the which occurs during use. This is done by creating nut on the screw and the more susceptible the unit a spacer threaded at one end with a is to nut wear. complimentary nut torsionally biased to advance when a gap develops.

The thread at the end of the spacer is a fine helix such that an axial load will not back drive the nut STIFF SPACER once spacer growth has occurred.

(L) The amount of preload on the unit is only that NUT HALF NUT HALF necessary to turn the spacer nut on the spacer rod and is independent of the external system loadings. We thus have a self-wear compensating unit which has extremely low frictional drag torque yet high axial stiffness. An alternate method replaces the spring with a stiff spacer sized to fit exactly between the two nut halves.

There is no excessive preload force at the interface and the unit is capable of carrying high axial loads in either direction with no backlash.

This is fine initially. However, as use time increases, wear begins on the nut threads causing a gap to develop between the spacer (L) and the nut halves.

www.huco.com 4 Leadscrews

Available Standard Metric Leads

The following table shows the range of standard metric leads available, non-standard leads can be manufactured subject to tooling charge.

Lead (mm) Diameter Series (mm) 0.5 1.0 1.4 1.5 2.0 2.5 3 4 5 6 7 8 10 12 14 15 16 19 20 24 25 50

03 4.76

04 6.35

06 9.53

07 11.11

08 12.7

10 15.88

12 19.05

14 22.23

Note: Imperial leads available to order.

Tel: +44 (0) 1992 501900 Leadscrews 5

ZBX Series - anti-backlash leadscrew assemblies

The patented Kerk ZBX Series anti-backlash assembly offers an effective linear actuator for design operations requiring precise positional accuracy and repeatability, with minimum cost. The standard ZBX unit utilises a patented self-lubricating polyacetal nut radially preloaded on a 303 stainless steel screw. The ZBX assembly, through its unique transfer of loads, offers exceptional torque consistency and repeatability when traversing in either direction. The inherent damping qualities of the ZBX design make it ideally suited for vertical applications requiring noise or vibration control. End machining to customer specifications and TFE screw coating are optional, as are designs for special operating configurations or environments.

ZBX Series - Flange Mount ZBX Series - Thread Mount

C

C N D DIA. D E E

120º F DIA. -3 HOLES TYP. ON G DIA. B.C. A B A DIA. B DIA.

M

ZBX Series - Flange Mount

Screw Diameter Nut Diameter Nut Length Flange Diameter Flange Thickness Mounting Hole Dia Bolt Circle Diameter Dynamic Load Drag Torque Series A B C D E F G kg Ncm mm mm mm mm mm mm mm ZBX.F.04M 6.35 12.7 25.4 25.4 4.6 3.6 19.1 2.3 0.4 - 1.0

ZBX.F.06M 9.52 17.8 48 38.1 4.6 5.08 28.6 5 1.0 - 2.0

ZBX.F.07M 11.11 20.3 48 38.1 4.6 5.08 28.6 7 1.5 - 3.0

ZBX.F.08M 12.70 22.6 50.8 41.2 6.6 5.08 31.8 11 1.5 - 3.0

ZBX.F.10M 15.88 26.9 50.8 44.5 6.6 5.08 34.9 16 2.0 - 5.0

ZBX Series - Thread Mount

Screw Diameter Nut Diameter Nut Length Flange Diameter Flange Thickness Thread Thread Length Dynamic Load Drag Torque Series A B C D E M N kg Ncm mm mm mm mm mm in -tpi* mm ZBX.Y.04M 6.35 12.7 33 20.3 5.6 5/8 - 18 4.1 2.3 0.4 - 1.0

ZBX.Y.06M 9.52 17.8 56 25.4 4.3 5/8 - 18 9.7 5 1.0 - 2.0

ZBX.Y.07M 11.11 20.3 59 25.4 3.1 15/16 - 16 9.7 7 1.5 - 3.0

ZBX.Y.08M 12.70 22.6 59 25.9 3.1 15/16 - 16 9.7 11 1.5 - 3.0

ZBX.Y.10M 15.88 26.9 61 26.9 3.8 15/16 - 16 12.7 16 2.0 - 5.0

* Metric threads available as required

To order specify Series required + Lead in mm + Overall Leadscrew Length in mm www.huco.com 6 Leadscrews

ZBA Series - anti-backlash leadscrew assemblies

The patented ZBA Series offers a can also be set at the factory to cost effective anti-backlash meet individual customer assembly for applications requiring specifications. The inherent precise positional accuracy and damping qualities of the ZBA repeatability. The ZBA has been design make it ideally suited for developed specifically for those applications requiring noise or applications that require very vibration control. smooth and consistent motion The standard ZBA unit utilises a such as printing, scanning, and co- self-lubricating polyacetal nut ordinate measurement systems. radially preloaded on a 303 An added benefit of the ZBA stainless steel crew. End design is the ability to manually machining to customer adjust the drag torque setting to specifications and TFE screw match the specific requirements of coating are optional. the application. This drag torque

ZBA Series - Flange Mount ZBA Series - Thread Mount

C C N E D DIA. F DIA. 3-HOLES D ON G DIA. B.C. E

A DIA. B DIA. A B

M

ZBA Series - Flange Mount

Screw Diameter Nut Diameter Nut Length Flange Diameter Flange Thickness Mounting Hole Dia Bolt Circle Diameter Dynamic Load Drag Torque Series A B C D E F G kg Ncm mm mm mm mm mm mm mm ZBA.F.04M 6.35 13.5 25.4 25.4 4.6 3.6 19.1 2.3 0.4 - 1.0

ZBA.F.06M 9.52 18.8 48 38.1 4.6 5.08 28.6 5 1.0 - 2.0

ZBA.F.07M 11.11 20.3 48 38.1 4.6 5.08 28.6 7 1.5 - 3.0

ZBA.F.08M 12.70 22.6 50.8 41.2 6.6 5.08 31.8 11 1.5 - 3.0

ZBA.F.10M 15.88 26.9 50.8 44.5 6.6 5.08 34.9 16 2.0 - 5.0

ZBA Series - Thread Mount

Screw Diameter Nut Diameter Nut Length Flange Diameter Flange Thickness Thread Thread Length Dynamic Load Drag Torque Series A B C D E F N kg Ncm mm mm mm mm mm in -tpi* mm ZBA.Y.04M 6.35 13.5 33 20.3 3.1 5/8 - 18 4.1 2.3 0.4 - 1.0

ZBA.Y.06M 9.52 18.8 56 25.4 3.8 5/8 - 18 9.7 5 1.0 - 2.0

ZBA.Y.07M 11.11 20.3 59 25.4 2.5 15/16 - 16 9.7 7 1.5 - 3.0

ZBA.Y.08M 12.70 22.6 59 25.9 2.5 15/16 - 16 9.7 11 1.5 - 3.0

ZBA.Y.10M 15.88 26.9 61 26.9 3.1 15/16 - 16 12.7 16 2.0 - 5.0

* Metric threads available as required

To order specify Series required + Lead in mm + Overall Leadscrew Length in mm

Tel: +44 (0) 1992 501900 Leadscrews 7

KHD Series - anti-backlash leadscrew assemblies

The Kerk KHD Series anti-backlash assembly makes use of Kerk’s patented AXIAL TAKE-UP MECHANISM (see page 3) to provide backlash compensation. The unique split nut with torsional take-up provides increased load capacity and axial stiffness over comparably sized ZBX units. Although the KHD offers high axial stiffness, frictional drag torque (0.7-2.0 Ncm) is very low. The anti-backlash mechanism in the KHD unit eliminates the need for load compensating preload forces. The assembly consists of a 303 stainless steel crew mated with a self-lubricating polyacetal nut. End machining to customer specifications and TFE screw coating are optional.

KHD Series - Flange Mount KHD Series - Thread Mount

C C E D DIA. M B DIA. 120º TYP. A DIA. B DIA. D DIA. A DIA.

E F DIA. -3 HOLES N ON G DIA. B.C.

KHD Series - Flange Mount

Screw Diameter Nut Diameter Nut Length Flange Diameter Flange Thickness Mounting Hole Dia Bolt Circle Diameter Dynamic Load Drag Torque Series A B C D E F G kg Ncm mm mm mm mm mm mm mm KHD.F.06M 9.53 20.3 50.8 38.1 4.8 5.08 28.58 10 0.7 - 2.0

KHD Series - Thread Mount

Screw Diameter Nut Diameter Nut Length Flange Diameter Flange Thickness Thread Thread Length Dynamic Load Drag Torque Series A B C D E M N kg Ncm mm mm mm mm mm in - tpi* mm KHD.Y.06M 9.53 20.3 55.80 19.1 1.27 3/4 - 20 8.9 10 0.7 - 2.0

* Metric threads available as required

To order specify Series required + Lead in mm + Overall Leadscrew Length in mm www.huco.com 8 Leadscrews

VHD Series - anti-backlash leadscrew assemblies

The KERK VHD Series anti-backlash assembly provides the maximum load carrying capability and the highest axial and radial stiffness of any Kerk nut assembly. Designed for smooth, quiet operation and long life, the VHD assembly provides low drag torque by making use of the patented Kerk AXIAL TAKE-UP MECHANISM (see page 3). Drag and wear associated with high pre-load forces are eliminated with the VHD Series. Screws are 303 stainless steel with Kerk’s custom TFE extended life coating optional. Assemblies are available cut-to-length or with screws machined to your requirements.

VHD Series - Flange Mount VHD Series - Thread Mount

C H C E D N 120º TYP.

J A B A DIA. B DIA.

F DIA. -3 HOLES M ON G DIA. B.C.

VHD Series - Flange Mount

Screw Diameter Nut Diameter Nut Length Flange Diameter Flange Thickness Mounting Hole Dia Bolt Circle Diameter Hub Hub ø Width Dynamic Load Drag Torque Series A B C D E F G J H kg Ncm mm mm mm mm mm mm mm mm mm VHD.F.08M 12.70 28.5 59 44.5 5.9 5.6 35.71 3.1 23.62 68 1.4 - 4.0

VHD.F.10M 15.88 35.1 66 53.9 7.6 5.6 44.45 N/A N/A 113 1.4 - 4.0

VHD.F.12M 19.05 41.2 71 60.5 7.9 5.6 50.8 N/A N/A 159 2.0 - 5.0

VHD Series - Thread Mount

Screw Diameter Nut Diameter Nut Length Thread Thread Length Dynamic Load Drag Torque Series A B C M N kg Ncm mm mm mm in - tpi* mm VHD.Y08M 12.70 28.5 64 15/16 - 16 12.7 68 1.4 - 4.0

VHD.Y.10M 15.88 35.1 72 1 1/4 - 16 12.7 113 1.4 - 4.0

VHD.Y.12M 19.05 41.2 79 1 3/8 - 16 12.7 159 2.0 - 5.0

* Metric threads available as required

To order specify Series required + Lead in mm + Overall Leadscrew Length in mm

Tel: +44 (0) 1992 501900 Leadscrews 9

NTB Series Ð Anti-Backlash Series

The Kerk NTB Series anti-backlash assembly is designed for higher load applications than the ZBX or KHD series units. Using Kerk’s patented take up mechanism, it maintains axial stiffness throughout its life while system torque is held to a minimum. The need to highly pre-load the nut to compensate for load has been eliminated with the Kerk NTB Series assembly. The nut is manufactured with a self lubricating polyacetal designed to run efficiently on Kerk’s precision rolled shafting. Screws are 303 stainless and are available with Kerk’s proprietary long-life TFE coating. Simple, compact design can be easily modified for custom applications. The NTB assembly provides low drag torque, high system stiffness, smooth operation, and long life throughout its load and speed range.

NTB Series - Flange Mount NTB Series - Flange Mount

C C D H D H E B E B 120º TYP. 120º TYP.

J A J A

F DIA. -3 HOLES ON G DIA. B.C. F DIA. -3 HOLES ON G DIA. B.C.

NTB Series - Flange Mount

Screw Diameter Nut Diameter Nut Length Flange Diameter Flange Thickness Mounting Hole Dia Bolt Circle Diameter Hub Hub ø Dynamic Drag Torque Width Load Series A B C D E F G J H Ncm mm mm mm mm mm mm mm mm mm kg NTB.F.04M 6.35 13.2 28 25.4 4 3.63 19.1 2.0 12.7 4.5 1.0 - 2.0 T R NTB.F.06M 9.52 20.3 45 38.1 5.1 5.08 28.6 2.6 19.1 9.1 1.0 - 2.0 I NTB.F.07M 11.11 22.9 46 41.2 5.7 5.08 31.8 2.6 22.23 13.6 1.0 - 2.0

NTB.F.08M 12.70 26.9 54 44.5 6.4 5.59 35.7 3.0 25.4 45.5 1.5 - 4.0

R NTB.F.10M 15.88 34.9 59 54.1 7 5.59 44.5 2.5 31.8 56.8 1.5 - 4.0 O U NTB.F.12M 19.05 39.6 67 60.5 7.9 5.59 50.8 2.5 38.1 68.2 2.0 - 5.0 N D NTB.F.14M 22.23 44.5 70 66.8 9.5 5.59 57.2 3.0 44.5 90.9 3.0 - 6.0

NTB.F.15M 23.81 44.5 70 66.8 9.5 5.59 57.2 3.0 44.5 90.9 3.0 - 6.0

NTB Series - Thread Mount

Screw Diameter Nut Diameter Nut Length Thread Thread Length Dynamic Load Drag Torque Series A B C M N kg Ncm mm mm mm in - tpi* mm NTB.Y.04M 6.35 13.2 28 7/16 - 20 6.4 4.5 1.0 - 2.0

NTB.Y06M 9.52 20.3 45 3/4 - 20 9.5 9.1 1.0 - 2.0 C NTB.Y.07M 11.11 22.9 46 13/16 - 16 9.5 13.6 1.0 - 2.0 B NTB.Y.08M 12.70 26.9 54 15/16 - 16 9.5 45.5 1.5 - 4.0 N

NTB.Y.10M 15.88 34.9 59 1 1/8 - 16 9.5 56.8 1.5 - 4.0

NTB.Y.12M 19.05 39.6 67 1 3/8 - 16 12.7 68.2 2.0 - 5.0 A

NTB.Y.14M 22.23 44.5 70 1 9/16 - 16 12.7 90.9 3.0 - 6.0

NTB.Y.15M 23.81 44.5 70 1 9/16 - 16 12.7 90.9 3.0 - 6.0 M * Metric threads available as required www.huco.com 10 Leadscrews

NTG Series Ð Anti-Backlash Series

The patented NTG Series offers a cost effective anti-backlash assembly for applications requiring precise positional accuracy, repeatability, and smoothness, The NTG has been developed specifically for demanding applications that require zero backlash with minimal drag torque. With its compact size and no moving components, the NTG can also be easily incorporated into customer specified, custom molded parts. An integral part of the NTG design is the ability to manually adjust the drag torque setting to match specific requirements of the application. This drag torque can also be set at the factory to meet individual customer specifications. The standard NTG unit utilises a self-lubricating polyacetal nut on a precision rolled 303 stainless steel screw. The NTG series is available in Mini, 6.35mm and 9.52mm sizes. End machining to customer specifications and TFE screw coating are optional.

NTGF Series - Flange Mount NTGY Series - Thread Mount

C C E D DIA. 120º N TYP.

A DIA. B DIA. A DIA. B DIA.

M F DIA. -3 HOLES ON G DIA. B.C.

NTGF Series - Flange Mount

Screw Diameter Nut Diameter Nut Length Flange Diameter Flange Thickness Mounting Hole Dia Bolt Circle Diameter Dynamic Load Drag Torque Series A B C D E F G kg Ncm mm mm mm mm mm mm mm NTG.F.04M 6.35 13.2 19 25.4 4 3.63 19.1 4.5 1.0 - 2.0

NTG.F.06M 9.52 20.3 25.4 38.1 5.1 5 28.6 9.1 1.0 - 2.0

NTGY Series - Thread Mount

Screw Diameter Nut Diameter Nut Length Thread Thread Length Dynamic Load Drag Torque Series A B C M N kg Ncm mm mm mm in - tpi* mm NTG.Y.04M 6.35 13.2 22 7/16 - 20 6.35 4.5 1.0 - 2.0

NTG.Y06M 9.52 20.3 30 3/4 - 20 9.53 9.1 1.0 - 2.0

* Metric threads available as required

Tel: +44 (0) 1992 501900 Leadscrews 11

BGP Series Ð General Purpose Series

The Kerk B Series general purpose assembly is for applications not requiring anti-backlash and wear compensation, It provides effective power transmission at minimum cost, and features long life, self-lubricating polyacetal nuts. The secure mounting and convenience of a circular flange is standard on the “B” nuts with triangular flange and thread mounting as an option. Many custom configurations are available. Screws are 303 stainless steel with Kerk’s extended life custom TFE coating optional. Assemblies can be supplied cut-to-length or with ends machined to customer requirements. Note: All B Series nuts are freewheeling.

BGP.F Series - Round Flange Mount

C D DIA. E 120º F DIA. -3 HOLES TYP. ON G DIA. B.C. A DIA. B

BGP Series - Round Flange Mount

Screw Diameter Nut Diameter Nut Length Flange Diameter Flange Thickness Mounting Hole Dia Bolt Circle Diameter Dynamic Load Series A B C D E F G kg mm mm mm mm mm mm mm BGP.F.04M 6.35 12.7 25.4 25.4 4.8 3.56 19.05 20

BGP.F.06M 9.52 15.9 25.4 28.6 4.8 3.56 22.23 35

BGP.F.07M 11.11 19.1 38.1 38.1 4.8 5.16 28.58 40

BGP.F.08M 12.70 19.1 38.1 38.1 4.8 5.16 28.58 68

BGP.F.10M 15.88 22.2 38.1 38.1 4.8 5.16 30.18 100

BGP.F.12M 19.05 28.6 50.8 44.5 6.4 5.16 36.53 160

BGP.F.14M 22.23 38.1 50.8 57.2 6.4 5.16 47.63 227

BGP.F.15M 23.81 38.1 50.8 57.2 6.4 5.16 47.63 227

To order specify Series required + Lead in mm + Overall Leadscrew Length in mm www.huco.com 12 Leadscrews

BGP Series Ð General Purpose

BGP.Z Series Triangular Flange Mount

C D DIA. E 120º F DIA. -3 HOLES TYP. ON G DIA. B.C.

A DIA. B DIA.

BGP Series - Triangular Flange Mount

Screw Diameter Nut Diameter Nut Length Flange Diameter Flange Thickness Mounting Hole Dia Bolt Circle Diameter Dynamic Load Series A B C D E F G kg mm mm mm mm mm mm mm

BGP.Z.04M 6.35 12.7 25.4 25.4 4.3 3.63 19.05 20

BGP.Z.06M 9.52 16.8 47 38.1 4.3 5 28.58 35

BGP.Z.07M 11.11 19.1 47 38.1 4.3 5 28.58 40

BGP.Z.08M 12.70 19.1 47 38.1 4.3 5 28.58 68

BGP.YM Series - Thread Mount

C

N

B DIA. A DIA.

M

BGP.YM Series - Thread Mount

Screw Diameter Nut Diameter Nut Length Thread Dia Thread Length Dynamic Load Series A B C M N kg mm mm mm size - pitch mm BGP.Y.04M 6.35 15.9 25.4 M12 x 1.25 6.4 20

BGP.Y.06M 9.52 19.1 25.4 M16 x 1.5 9.5 35

BGP.Y.07M 11.11 25.4 38.1 M20 x 1.5 9.5 40

BGP.Y.08M 12.70 25.4 38.1 M20 x 1.5 9.5 68

BGP.Y.10M 15.88 25.4 38.1 M24 x 2 9.5 100

BGP.Y.12M 19.05 38.1 50.8 M30 x 3.5 12.7 160

BGP.Y.14M 22.23 38.1 50.8 M30 x 3.5 12.7 227

BGP.Y.15M 23.81 38.1 50.8 M30 x 3.5 12.7 227

Tel: +44 (0) 1992 501900 Leadscrews 13

Mini Series

The Mini Series brings Kerk quality, precision and value to products that were previously off limits to lead screw technology. To meet a wide range of applications, the Mini Series includes anti-backlash and standard assemblies. • Using Kerk’s patented take-up mechanism, the self- compensating NTB maintains axial stiffness throughout its life while system torque is held to a minimum. • The NTG allows drag torque to be pre-set according to system requirements. • The Mini BGP Series is for applications not requiring anti-backlash and wear compensation. All Mini Series assemblies include 303 stainless steel lead screws, available with Kerk’s proprietary, long-life TFE coating. All the nuts are maintenance free, manufactured with self-lubricating polyacetal, and designed to run smoothly and efficiently on Kerk’s precision rolled screws. Perfect for demanding applications, the Mini NTB and NTG nuts provide zero backlash with drag torque of less than 0.4 Ncm. Kerk’s Mini Series has what it takes for affordable, precision motion control, sized to fit and built to last.

Mini Series

C D

B G F

A D1D 1 E

Mini Series

Screw Diameter Nut Diameter Nut Length Flange Height Flange Width Flange Thickness Slot Width Bolt Circle Dynamic Drag Diameter Series Load Torque A B C D1 D E F G mm mm mm mm mm mm mm mm kg Ncm NTB.F.02M 3.18 10.2 12.7 10.2 19.1 3.2 3.05 15.24 2.3 0.4

NTB.F.03M 4.76 10.2 12.7 10.2 19.1 3.2 3.05 15.24 2.3 0.4

NTG.F.02M 3.18 10.2 12.7 10.2 19.1 3.2 3.05 15.24 2.3 0.4

NTG.F.03M 4.76 10.2 12.7 10.2 19.1 3.2 3.05 15.24 2.3 0.4

BGP.02M 3.18 10.2 13 10.2 19.1 3.2 3.05 15.24 11 free wheeling

BGP.03M 4.76 10.2 13 10.2 19.1 3.2 3.05 15.24 11 free wheeling

www.huco.com 14 Leadscrews & Linear Rails

Kerk Screwrail

Linear motion has traditionally required separate components to lower component costs and reduced labour. handle both drive and support/guidance. The patented Kerk The ScrewRail consists of a precision rolled lead screw, ScrewRail(tm) combines both functions in a single, coaxial supported by sealed bearings and contained within a concentric component. By eliminating the need for external rail-to-screw steel guide rail, driving an integrated nut/bushing. Because all the alignment, the ScrewRail simplifies the design, manufacture and alignment requirements are achieved within the ScrewRail, assembly of motion systems. The ScrewRail’s coaxial design support and positioning of the SCREWRAIL is much less critical saves as much as 80% of the space used by a two-rail system than with traditional slide assemblies. TFE coating and self- and is generally less expensive than the equivalent components lubricating nut/bushing materials ensure long life without purchased separately. The savings can be substantial due to maintenance.

SRA Series A standard nut for general applications where anti-backlash is not required. The SRA is recommended anywhere where low drag and minimal free play is required. NOTE: TOTAL TRAVEL = L - (L1 + L2 + E)

B L L1 L2 E H (B.C.D.) I DIA. F

MAX D DIA. G NUT DIA. C DIA.

A DIA. SRA Series

Flange Max. Nut Pitch Circle Bolt Hole Rail Diameter Spigot Length Spigot Dia Flange Dia Nut Length Thickness Diameter Diameter Diameter Series A B C D E L1 L2 F G H I mm mm mm mm mm mm mm mm mm mm mm SRA.G.04 12.472/12.496 15.75 4.750/4.762 31.8 36 9.5 20.3 26.2 3.56 6.6 9.1

SRA.G.06 18.822/18.846 19.05 6.325/6.337 44.5 51 12.7 30.5 37.6 4.39 9.7 17.8

SRA.G.08 25.172/25.196 19.05 6.325/6.337 56.7 64 15.9 40.7 48.8 5.08 12.2 19.6

SRZ Series A nut with Kerk's patented axial take-up mechanism providing continuous self adjusting anti-backlash properties.

NOTE: TOTAL TRAVEL = L - (L1 + L2 + E)

B L L1 L2 E H (B.C.D.)H (pcd) F I DIA.

D DIA. C DIA.

A DIA. G DIA.

SRZ Series

Flange Max. Nut Pitch Circle Bolt Hole Rail Diameter Spigot Length Spigot Dia Flange Dia Nut Length Thickness Diameter Diameter Diameter Series A B C D E L1 L2 F G H I mm mm mm mm mm mm mm mm mm mm Brass Inserts SRZ.F.04 12.472/12.496 15.75 4.750/4.762 31.8 36 9.5 24.7 26.2 6-32 6.6 9.1

SRZ.F.06 18.822/18.846 19.05 6.325/6.337 44.5 51 12.7 35.1 37.6 10-32 9.7 17.8

SRZ.F.08 25.172/25.196 19.05 6.325/6.337 56.7 64 15.9 43.7 48.8 10-32 12.2 19.6

Tel: +44 (0) 1992 501900 Screwrails 15

End Supports

As an additional option for all Kerk ScrewRail’s, standard End Supports offer the convenience of simple and compact mounting for the ScrewRail. The End Supports are designed to slide over the outside diameter of each end of the rail and “key” off the slot in the ScrewRail. The carbon reinforced polyacetal End Supports come standard with three hex nuts that are captured in the flange for easy assembly. The End Supports are also supplied with a brass threaded insert and a set screw to fasten to the outside diameter of the rail. With the End Supports, the Kerk ScrewRail can be easily mounted to your assembly. However, if the End Supports are not utilised it is recommended to centre the clamping force on each end at the L3 dimension as shown in the drawing below

Typical End Supports

P=L+2R Q P Q S Hex Nut On F' F' T (B.C.D.) (pcd) R E R H' DIA. A W rad. Y (2 places) A' DIA. A' DIA.

D' DIA. A X L3 L3 U (Brass Insert) L4 L4 for Set Screw L

Dimensions E and L are referenced in the ScrewRail Dimensions section View A-A Note: Total Travel=L-(E+2(L4))

Typical End Supports

End Spigot Flange Flange Bolt Hole Set Screw Bore Spigot End Hex Pitch Circle Thread Lobe Width Length Item Diameter Diameter Thickness Diameter Position Depth Length Thickness Nut Diameter Size Radius Series Number A D F H L3 L4 Q R S T U W X Y mm mm mm mm mm mm mm mm mm mm mm mm mm 04 SR04ES 15.85/15.9 34.3 5.08 3.81 9.91 18.29 2.03 1.52 6-32 26.2 8-32 12 11.68 12.7

06 SR06ES 19.03/19.08 40.6 6.35 4.39 15.32 22.86 2.54 2.54 8-32 33.3 10-32 15.3 15.09 16.38

08 SR08ES 25.38/25.43 55.9 9.53 5.08 23.37 30.48 3.18 4.45 10-32 46.2 10-32 20.9 20.32 20.83

www.huco.com 16 Linear Rails

Linear Support Rails

The Kerk LR Series linear rail system has been designed for light load applications where low cost, minimum frictional drag and long wear life are primary design considerations. The assembly consists of a centreless ground and burnished stainless steel shaft mated with a graphite and PTFE filled thermoplastic bushing. The material combinations have been selected so that thermal fluctuations have minimal effect on system performance. Additional lubricity and extended life can be obtained by using Kerk’s low friction TFE coating on support shafts available in both stainless and alloy steel. Standard shaft straightness is (0.05mm) per foot and typical radial clearance between shaft and bushing is (.013mm) on non-coated assemblies and (.025mm) on TFE coated assemblies. Bushings are manufactured with standard retaining ring grooves.

Linear Support Rails

C

E G TYP. B

A

D

F TYP. .030 x 45º TYP.

LR Linear Rails

Standard Rail Rail Diameter Bush O.D. Bush Bush I.D. Snap Ring Snap Ring Rail Chamfer Radial Load Groove Width. Lengths Diameter with TFE Coat Length Groove Loc. Groove Dia. Series mm kg (Approx) mm mm mm mm mm mm mm mm mm Tolerances mm – 0.015 0.015 0.013 0.25 0.013 0.25 0.100 0.008 – –

LR.04 150,200,250,300 6.29 6.28 12.7 19.43 6.31 13.59 11.43 1.02 0.51 2.3

LR.06 150,300,380,450 9.44 9.43 19.05 32.39 9.46 25.27 17.17 1.17 0.51 4.5

LR.08 300,380,450,610 12.61 12.60 25.4 42.16 12.64 33.78 22.86 1.17 0.51 6.8

LR.12 450,610,920 18.83 18.83 31.75 51.72 18.86 41.15 28.6 1.47 0.76 11.4

Tel: +44 (0) 1992 501900 Spline Shafts 17

Spline Shafts

The Kerk Spline Shaft (SS) series spline shaft system has been designed for light load applications, where low cost, low friction, and long life are primary design considerations. The assembly consists of a lightweight, aluminium, spline shaft treated with Kerk’s proprietary low friction TFE coating, mated with a graphite and PTFE filled thermoplastic bushing. The bushing is supplied with an integral brass collar to facilitate various mounting configurations without nut distortion. Standard shaft straightness is 0.08mm per 300mm. Typical radial and torsional clearance between shaft and bushing for a basic assembly (SSB) is 0.05mm to 0.08mm. An anti-backlash assembly (SSZ) is available for applications requiring additional system stiffness. As with all Kerk assemblies, special bushing configurations and end machining configurations are available upon request.

Spline Shafts

Type SSBP - Basic Style Plain Diameter Mount Type SSZP - Anti-backlash Plain Diameter Mount

Type SSBY - Basic Style Thread Mount Type SSZY - Anti-backlash Thread Mount

SS Spline Shafts

Shaft Diameter Bush O.D. Bush Length Thread Nut Length Series UNF E mm mm mm mm

SS.04 6.35 12.7 19.1 7/16-20 6.35

SS.06 9.53 15.88 25.4 9/16-20 9.53

SS.08 12.7 20.65 38.1 3/4-20 12.7 www.huco.com 18 Leadscrews & Linear Rails

Design and Engineering Data

Screw Accuracy Kerk uses a unique precision rolling process for screw manufacturing. Standard lead accuracy for Kerk screws is .0006 mm/mm. Lead accuracies are available up to .0001 mm/mm. Kerk can provide laser-interferometer generated mapping for our screws. Assemblies have an extremely high bi-directional repeatability of .0013mm. End Machining Kerk can custom machine screws to your specifications or provide cut-to-length screws for your own machining. Critical Speed This is the rotational speed at which a screw may experience vibration or other dynamic problems. See CRITICAL SPEED CHART to determine if application parameters result in speed approaching critical. To minimise critical speed problems: use a longer lead, choose a larger diameter or increase bearing mount support.

CRITICAL SPEED 3000

2000

1000 800 600 10000 SERIES 400 4000 SERIES 12000 SERIES 14000 SERIES 200 8000 SERIES

Revolutions Per Minute 7000 SERIES 80 Percent Critical Speed 100 80 6000 SERIES 60

40 30

Rigid/Free 12 2440 36 48 60 72 84 96 108 120 Simple/Simple 20 48 60 80 100 120 140 160 180 200 Rigid/Simple 24 60 73 97 121 145 170 194 218 242 Rigid/Rigid 30 90 119 149 179 209 239 269 298 Column Length Between Bearings (Inches) Adjusted for Bearing Support

RigidFree SimpleSimple Rigid Simple Rigid Rigid

Least Support Most Support

Lengths Lengths can be specified up to 2m (depending on diameter and lead). ‘Cut to length’ screws are offered in 150mm increments. Lead Advancement per revolution. All screws are listed by lead, not pitch. Lead = Pitch x Number of Starts Pitch Crest-to-crest distance. (On a multiple start thread, the pitch equals the lead divided by the number of starts.)

Tel: +44 (0) 1992 501900 Leadscrews & Linear Rails 19

Traverse Speed The nut materials we use provide long wear-life over a wide variety of conditions. However, very high loads and/or speeds will accelerate nut wear. Special materials may be required for these situations. We offer the following guidelines for continuous duty linear traversing speeds for optimum life: Lead Traverse Speed 1-12mm 100mm/sec. 12-25mm 250mm/sec. 25-60mm 760mm/sec. Maximum Load Although Kerk Anti-backlash Assemblies are capable of withstanding relatively high loads without catastrophic failure, these units have been designed to operate under the loading shown in the size charts. Efficiency Efficiency is the relationship of work input to work output. It should not be confused with mechanical advantage. Listed efficiencies are theoretical values based on TFE coated screws.

Torque The required motor torque to drive a lead screw assembly is the sum of three components: the inertial torque, drag torque, and torque to move load. It must be noted that this is the torque necessary to drive the lead screw assembly alone. Additional torque associated with driving frictional bearings and motor shafts, moving components, and drag due to general assembly misalignment must also be considered.

Inertial Torque α Tj = I Where I = screw inertia α = angular acceleration

Drag Torque Kerk Anti-backlash Assemblies are typically supplied with drag torque of 1 to 5Ncm. The magnitude of the drag torque is dependent on the standard factory settings or settings specified by the customer. Generally, the higher the preset force, the better the Anti-Backlash characteristics.

Torque-To-Move Load:

LOAD x LEAD TL = 2π x EFFICIENCY

Back Driving Sometimes referred to as reversibility, back driving is the ability of a screw to be turned by a thrust load applied to the nut. Generally, back driving will not occur when the screw lead is less than 1/3 the diameter for uncoated screws or 1/4 the diameter for TFE coated screws. For higher leads where back driving is likely, the torque required for holding a load is:

LOAD x LEAD x EFFICIENCY Tb = 2π

Screw Straightness Screw Straightness is measured as Total Indicator Runout(TIR). The standard Kerk straightness for lead screws is 0.08mm per 300mm. Kerk can provide tighter specifications on customer request. All screws are hand straightened before shipping.

www.huco.com Other Qualtiy Products from Huco

SPACERS PILLARS AND STAND-OFFS

Please call 01992 501900 for any of our brochures

Huco Engineering Industries Ltd. Merchant Drive, Hertford, Herts SG13 7BL Tel: +44 (0) 1992 501900 Fax: +44 (0) 1992 509890 Email: [email protected] www.huco.com

© 20032002 Huco Engineering Industries Ltd Printed in the U.K.