Used Universal Gear Hobbing Machine for sale (69,650)

Condition: used, Year of construction: 1995, max. wheel diameter 80 mm gear width 120 mm max. module 3 min. module 1 control SIEMENS 840 C total power requirement 30 kW weight of the machine ca. 7500 t dimensions of the machine ca. m L I E B H E R R CNC – Controlled Gear Hobbing Machine Type LC 82 Baujahr 1995 Ser.-Nr. 0836 _____ Gear-Diam. max. 80 mm Module Range 1 - 3 Helix Angle +/- 45 ° Distance Table Center to Tool Center 15 – 160 mm Hobbing Head Slide stroke vertical 250 mm Tangential Travel / Shift Travel of Tool slide 180 mm Minimum Number of Teeth 3 (!) Hob Size max. Ø x length approx. 90 - 200 mm Taper of Hob spindle HSK 50 A Workpiece Clamping length (table/Tailstock) 250 mm Infeed rates axial/radial/tangential/ 20/4/5/ mm/WP rev. Hob speed steplessly adjustable 0 – 800 rpm Hob Spindle Drive 8 kW - Total Load approx. 30 kW - 400 V – 50 Hz Total weight of Machine approx. 7.500 kg Special attachments / accessories: • SIEMENS - CNC-Control Model 840 C for 6 axis (i.e. Hob drive/table drive/ Njdpot Hw R Dofx Ah Hswb swivel angle of hob head/ Radial axis/Axial Axis/ Tangential Axis ) with a surface especially designed for the gear manufacturing with error display function. • Automatic and contactless tooth meshing device to adjust the hob into workpiece. • Automatic Shifting of hob slide. • Automatic Workpiece handling system Model SSL for high speed loading and unloading of Workpieces, consisting of a steel chain3,, for workpiece carriers and 3-fold WP-Gripper for blanks, for the machining position and for unloading of finished parts onto the steel band. Actual Workpiece size to be machined: approx.. Ø 30 x 120 mm length, helix gear sprocket. Clamping of workpiece between centers by a mechanical, cam controlled quill in tailstock. • complete workarea protection with one sliding door, chip conveyor, small coolant device, oil dust Absorber, WP Carrier, etc. The Machine can be also used for dry cutting. Condition : Satisfactory to Good . Machine can be inspected under power here in stock. Delivery : Ex stock, as inspected. Payment : Net, after conclusion of contract.

Condition: used, Year of construction: 1992, max. wheel diameter 150 mm gear width 300 mm max. module 4,5 min. module total power requirement 20 kW Nwodpot Hwxbefx Ah Heb weight of the machine ca. 6 t dimensions of the machine ca. m

Condition: ready for operation (used), Year of construction: 1992, functionality: fully functional, machine/vehicle number: 27498, feed length X-axis: 230 mm, feed length Y-axis: 170 mm, feed length Z-axis: 400 mm, gear diameter: 130 mm, spindle speed (max.): 1,200 rpm, TECHNICAL DETAILS Gear diameter: max. 130 mm Gear width: 400 mm Module: 0.5 - 3 Clamping length: max. 1,160 mm Work spindle swivel angle: ± 45° Tool change swivel angle: 90° Workpiece Largest module (in steel with approximately 600 N/mm²): 4 Largest swing diameter (not millable): 480 Smallest number of millable teeth: 3 Tool Largest hob diameter: 130 mm Largest cutter length (depending on cutter arbor diameter): 220 mm Cutter arbor diameter: 16 / 22 / 27 / 32 mm Cutter arbor taper: ISO Workpiece spindle – WS External turning range: 160 mm Bore: 63 mm Tailstock – RT Motorized travel (W-axis): 750 mm Quill stroke (hydraulic): 90 mm Axis travels X-travel: 230 mm Y-travel: 170 mm Z-travel: 400 mm Spindle Cutter speed (infinitely variable): 300 – 1,200 rpm Workpiece spindle speed range: 1 – 125 rpm Control system Control system: Bosch CC 220 MACHINE DETAILS Total power requirement: 52 kW Machine weight: approx. 7.5 t Machine dimensions: approx. 4,800 × 3,800 × 2,500 mm Space required: 7.3 x 5.3 x 4.3 m Operating voltage: 380 V Nwodpfswc Tduox Ah Hjb Control voltage: 220 V V Frequency: 50 Hz Machine power consumption: approx. 56 kVA EQUIPMENT - Bosch CC 220 CNC control - Continuously variable cutter speed control - Large travel range in all axes - High flexibility thanks to a wide range of modules

Condition: excellent (used), Max. Wheel Dia: 1600 mm Nsdpfsv Igc Nsx Ah Howb Min. wheel Dia: 800 mm Gear width: 560 mm Max. module: 16 Min. Module: 4 Table dia: 1350 mm Table load cap: 7000 Kg Machine weight: ca. 18 Tonnes Machine with change gear, arbors, fixtures set Machine is in excellent condition

Condition: ready for operation (used), Gear hobbing machine type FD320, FD500 and FD 800 Cugir Maximum module 6 to 10 mm Max. working diameter 320 to 800 mm Nedpfx Ascrd Nmjh Hswb

Condition: good (used), WANDERER 16/E milling machine, made in Germany. Year of manufacture: 1962. The machine is operational and in working condition. For more information, please contact us. Nsdpfxew Al U Es Ah Hswb

Condition: ready for operation (used), Manufacturer LIEBHERR Model L 652 Year 1980 Condition Used Serial number 0674/5 Max workable diameter 650 mm Max module 10 Hobber shifting 200 mm Hobber diameter 192 mm Hobber length 250 mm Nedpfjwp Rttex Ah Hewb Machine weight 11200 Kg Equipment: spare gears instruction manual

Condition: good (used), Liebherr - Lorenz S800 Gear Hobbing Machine -Well-maintained machine with comprehensive accessories -1x pallet of change gears -1x pallet of hobbing cutters -1x pallet of arbors -DOCUMENTATION -Max. workpiece length with counter support: 600 mm -Max. workpiece length with counter support retracted: 800 mm -Max. travel of the milling slide: 360 mm -Largest pitch machinable with largest workpiece: 5 Pi / in standard range: 8 Pi -Spindle taper - milling spindle: MT 5 -Arbors: 22/27/32/40 mm -Max. cutter diameter: 186 mm -Max. cutter length: 170 mm -Max. cutter shift: 80 mm -Cutter speeds: 40-220 rpm -Feed rates steplessly adjustable / horizontal -Feed rates steplessly adjustable / vertical -Feed rates steplessly adjustable / tangential -Clamping table without coolant rim: 550 mm Njdpfxow R Tykj Ah Hjwb -Clamping table bore: 100 mm -Clamping arbor taper: MT5 Dimensions: LxWxH 3.6 x 1.8 x 1.9 meters / Weight 5000 kg Subject to errors and input mistakes.

Year of construction: 1984, condition: ready for operation (used), A Pfauter vertical CNC gear hobbing machine is available. Modules min./max.: 1/3, max. workpiece diameter: 150mm, max. tooth width: 150mm, milling head tilt: +/-45°, milling cutter axis-table axis distance: 10mm-160mm, table diameter: 160mm, table bore: 63mm. Tool holder: SK40, max. cutter diameter: 130mm, max. cutter length: 220mm, speed: 600rpm, feed: 1500mm/min, tangential path: 170mm, rapid traverse: 3m/min. Machine dimensions X/Y/Z: approx. 4000mm/3000mm/2500mm, weight: approx. 6500kg. On-site inspection is possible. Njdpswkih Eofx Ah Howb

Condition: reconditioned (used), Year of construction: 1991, functionality: fully functional, machine/vehicle number: 27604, feed length Y-axis: 170 mm, feed length Z-axis: 200 mm, table diameter: 160 mm, spindle speed (max.): 600 rpm, TECHNICAL DETAILS X-axis: 150 mm Y-axis: 170 mm Z-axis: 200 mm Swivel angle: -150/30° Milling unit Max. hob diameter: 130 mm Max. hob length (shaft mill): 220 mm Max. module: 3 Cutter length: max. 220 mm Cutter speeds: continuously variable up to 600 rpm Milling arbor diameter: 32 mm Table Table diameter: 160 mm Table bore diameter: 63 mm Control & Retrofit Nwedpfx Aov Rdwioh Hjb Control: SINUMERIK 840 D SIEMENS Retrofit: Sinumerik 840 D / Windows XP Pro in 2010 MACHINE DETAILS Total power requirement: approx. 20 kW Machine weight: approx. 10,500 kg Space required: approx. 6.8 x 3.7 x 2.85 m

Condition: ready for operation (used), Year of construction: 1981, functionality: fully functional, VEB Fritz Heckert ZFWVG 250×2000 Nwsdpfx Ahow Dvanj Hob Maximum workpiece length: 2,000 mm Maximum workpiece diameter: 250 mm Accessories: 2nd milling head, hob cutters in various modules, steadies, clamping devices, etc.

Condition: like new (used), Year of construction: 2004, More Photos coming soon hob cutter: -Largest permissible tip circle diameter: 80 mm Largest toothed length: 70 mm Largest total length: 240 mm Taper for trimming with counter bearing steep taper 1:3, 4286 Mounting diameter of the collet: 32 mm Sliding paths: Nodpfx Ahjqpf Ifj Hewb Radial (X-axis): 100 mm Tangential (Y-axis): 160 mm Axial (Z-axis): 300 mm Tailstock (Z4 axis): 350 mm Loading gantry (X5 axis) 3800 mm Largest milling head swivel angle: Direction +A: 40 degrees Direction A: 40 degrees Workpiece spindle: Outer diameter: 160 mm Bore: 63 mm Overall dimensions of the machine: Length: 9130 mm Width: 3895 mm Height: 3200 mm Gain of the machine: 8400 kg Feed rates: X and Z axes: 1 to 10000 mm/min Y axis: 1 to 5000 mm/min Rapid traverse: X, Z and Z4 axes: 10000 mm/min Y axis: 5000 mm/min X5 axis: 150 mm/min Speeds: Tool: 300 to 4000 min^-1 Workpiece spindle: 0 to 1000 min^-1 Operating voltage: 400 V Supply voltage: 230 V Control voltage: 24 V Frequency: 50 Hz Connected load of the machine: 48 kVA Cable cross-section: 35 mm2 Fuse protection: 70A wälzfräser: -Großter zulassiger Kopfkreissdurchmesser: 80 mm Groste verzanne Lange: 70 mm Größte Gesamtange: 240 mm Kegel zum Abstutzen m Gegenlager Steilkegel 1:3, 4286 Aufnahmedurchmesser der Spannzange: 32 mm Schlitterwege: Radial (X-Achse): 100 mm Tangential (Y-Achse): 160 mm Axial (Z-Achse): 300 mm Reitstock (Z4-Achse): 350 mm Ladeportal (X5-Achse) 3800 mm Größter Fräskopfschwenkwinkel: Richung +A: 40 Grad Richtung-A: 40 Grad Werkstückspindel: Außendurchmesser: 160 mm Bohrung: 63 mm Gesamtabmessungen der Maschine: Lange: 9130 mm Breite: 3895 mm Höhe: 3200 mm Gewinnt der Maschine: 8400 Kg Vorschübe: Achsen X und Z: 1 bis 10000 mm/min Achse Y: 1 bis 5000 mm/min Eilgänge: Achsen X, Z und Z4: 10000 mm/min Y.Achse: 5000 mm/min X5-Achse: 150 mm/min Drehzahlen: Werkzeug: 300 bis 4000 min^-1 Werkstückspindel: 0 bis 1000 min^-1 Betriebsspannung: 400 V Versorgungspannung: 230 V Steuerspannung: 24 V Frequenz: 50 Hz Anschlußwert der Maschine: 48 kVA Kabelquerschnitt: 35 mm2 Absicherung: 70A

Condition: excellent (used), Year of construction: 1991, functionality: fully functional, Machine still under power and production can be seen at any time. Technical Data – PE 150 This hobbing machine with automatic workpiece change system is designed for series production of workpieces, for which the corresponding drawings have been received. Our specialists for automatic workpiece changing systems will gladly assist you if you wish to convert the machine for milling different workpieces. Hob Cutter: Max. permitted cutter outside diameter: 130 mm Max. length (depending on cutter arbor diameter): 220 mm Slide Travel: Radial (X-axis): 150 mm Tangential (Y-axis): 170 mm Axial (Z-axis): 200 mm Max. Swivel Angle of Milling Head: In +A direction: 30° In -A direction: 45° Workpiece Table: Outer diameter: 160 mm Bore diameter: 63 mm Overall Dimensions of the Machine: Length: 5,820 mm Width: 4,047 mm Height: 2,810 mm Approximate Weight of Machine: 8,000 kg Nedpfx Aeu N E Rreh Hewb Speeds: Feeds: Axes X, Y, and Z: 1 to 3,000 mm/min Rapid Traverses: Axes X, Y, and Z: 3,000 mm/min Spindle Speeds: Tool (S-spindle): 150 to 600 rpm Workpiece table (C-axis): 1 to 125 rpm Electrical Equipment: Operating voltage: 400 V Supply voltage: 230 V Control voltage: 24 V Frequency: 50 Hz Connected load of the machine: 48.5 kVA Cable cross-section: 25 mm² Fusing: 100 A

Condition: used, Horizontal Gear Hobbing Machine WMW MODUL ZFWZ 1250/3 Nwedpfx Ahowxxxcj Hsb Year of manufacture: 1982 Control: conventional Country of origin: Germany Max. gear diameter: 1250 mm Gear width: 600 mm Module – max.: 16 Module – min.: 2 Cutter diameter: 240 x 280 mm Table clamping surface: 1020 mm Speed range: 28 – 200 rpm Axial feeds: 0.28 – 8 mm/min Radial feeds: 0.1 – 2 mm/min Tangential feeds: 0.16 – 4 mm/min Swivel range of milling slide - L/R: +/- 45° Rapid traverse motor: 12.5 kW Voltage: 380 V Frequency: 50 Hz Total power requirement: 5/19.5 kW

Condition: ready for operation (used), Year of construction: 2004, operating hours: 18,396 h, functionality: fully functional, travel distance X-axis: 650 mm, travel distance Y-axis: 450 mm, travel distance Z-axis: 450 mm, controller model: Heidenhain 530, number of axes: 3, In 2022, the tool magazine door was replaced. In 2023, the SIMODRIVE 611/18A servo converter was replaced! TECHNICAL DETAILS Travel X-axis: 650 mm Travel Y-axis: 450 mm Travel Z-axis: 450 mm Tool holder: SK 40 Number of axes: 3 MACHINE DETAILS Control: Heidenhain 530 Operating hours Nwjdpfx Ahsx Up E Es Heb Spindle hours: 18,396 Machine hours: 56,040

Condition: ready for operation (used), Year of construction: 1997, functionality: fully functional, travel distance X-axis: 660 mm, travel distance Y-axis: 500 mm, travel distance Z-axis: 600 mm, controller model: PHILIPS CNC 532, Equipment: chip conveyor, TECHNICAL DETAILS X-axis travel: 660 mm Y-axis travel: 500 mm Z-axis travel: 600 mm Nsdpfjya Hcqox Ah Hjwb Table clamping surface: 630 x 500 mm Spindle taper: SK 40 Spindle speeds: 20 - 6,300 rpm Feed rate: 30 m/min MACHINE DETAILS Control: PHILIPS CNC 532 Internal coolant supply: 40 bar Total power requirement: 50 kW Dimensions & weight Machine dimensions: 4.98 x 2.78 x 2.93 m Machine weight: approx. 13.3 t EQUIPMENT Chip conveyor Coolant system Rotary pallet changer Hydraulic swivel head (horizontal/vertical)

Condition: good (used), Year of construction: 2007, max. wheel diameter 500 mm gear width 200-400 mm module 12 turning speeds 0-3250 U/min bracke pressure bis max. 95 Nm inner taper Konus #39 Control Fanuc 16 total power requirement 15 kW weight of the machine ca. 6 t dimensions of the machine ca. 2.350 x 2.240 x 2.500 mm HIGHLY FLEXIBLE TESTING OF HARD, FINISHED AND GREEN SPIRAL BEVEL AND HYPOID GEAR SETS Nodpfx Ahsvr Hf Ej Howb The T 60 bevel gear testing machine is a CNC testing machine with three linear axes for the fully automatic hard and soft testing of spiral bevel and hypoid gear sets with a 90° axis angle. It offers versatile objective and subjective testing options with speeds up to 3,250 min and braking torques up to max. 95 Nm.

Condition: ready for operation (used), Year of construction: 2003, functionality: fully functional, Portal Machining Center – Universal – 5-axis machining Brand: AXA / Type: VPC-40-U / Year of construction: 2003 Description: Compact gantry design with overhead guides,automatic 1-axis swivel head and integrated NC rotary table for 5-sided machining. Condition: Ready for use / operational Operating hours (switch-on time): approx. 63.400 h TECHNICAL DATA Machining paths: - X-path (longitudinal movement): 2.300 mm vertical / 2.000 mm horizontal - Y-path (cross movement): 1.200 mm - Z-path (vertical movement): 600 mm - Distance between table and spindle nose: Zmin vert./hori. 110/160 mm - Rotary table – spindle nose: Zmin vert./hori. 110/160 mm Working table: - Table clamping surface: 1.100 x 1.100 mm - Table load: 1,5 tons Feed rates: - Max. Feed force: 9.000 N - Rapid traverse in X/Y/Z: 20/20/20 m/min Main drive / Spindle head: - Main drive AC – Hollow shaft motor 40 % ED: 30 kW - Speed range, continuously variable: 30 – 10.000 rpm - Tool holder: SK 40, DIN 69871A / 69872A Tool changer (chain magazine) Nedpfjydq Hhex Ah Howb - Tool stations: 36 positions Working spindle: 1-axis swivel head with 1° pitch Hirth spline instead of the standard 2.5° pitch. NC - Horizontal rotary table integrated into the machine table: - Rectangular face plate 1.100 x 1.100 mm EQUIPMENT / ACCESSORIES: - CNC-Control: Heidenhain iTNC 530 - Table height increase: fixed table by 150 mm. This means that the top edge of the fixed table and the rotary table are at the same height. - Coolant through the spindle - Chip conveyor (hinged belt) - Integrated 200 l coolant tank with pump for external cooling - Full machine enclosure - Extraction unit for extraction on both sides with work area enclosure - Manual spray guns - Electric hand wheel - Tool probe system TT 130, brand: Heidenhain There is no guarantee for correctness and completeness of the technical details and accessories. - Subject to prior sale - Detailed technical data sheet and information on equipment available on request.

Condition: used, Year of construction: 2005, control Heidenhain x-travel 900 mm y-travel 900 mm Nedpfx Aoydqrkjh Hswb z-travel 500 mm a-axis -30/+110 ° c-axis 360 ° table diameter 800 mm table load 1.000 kg spindle tunring speed 18.000 U/min spindle drive 40 kW torque 137/100 Nm tool taper HSK-63 A number of tool places 30 Pos. max. tool diameter 90 mm max. tool length 300 mm max. tool weight 10 kg In our assessment, the machine is in good used condition and can be inspected under power by appointment. Accessories, tools, and clamping devices shown are only included in the scope of delivery if this is noted in the additional information. Technical data and specifications are subject to change without notice. Prior sale is reserved.

Condition: used, Year of construction: 2007, x-travel 600 mm y-travel 500 mm z-travel 500 mm Control Heidenhain iTNC 530 spindle tunring speed 15.000 U/min max. torque 190 Nm tool taper HSK 63 table surface area 600 x 600 mm table load capacity 350 kg feed 60.000 mm/min auto power on hours ca. 7.975 h NC program ON ca. 1.999 h spindle hours ca. 1.378 h weight of the machine ca. 9.800 kg Overall size ca. 5.000 x 4.500 x 3.110 mm In our assessment, the machine is in good used condition and can be inspected under power by appointment. Nwjdpfxsydqq Ts Ah Hsb Technical features & accessories: - External coolant system with 3 nozzles, 4 bar - Internal coolant system, 20 bar - Scraper belt chip conveyor Accessories, tools, and clamping devices shown are only included if specifically stated in the additional information. Technical data and specifications are subject to change without notice. Prior sale is reserved.

Condition: used, Year of construction: 2009, x-travel 500 mm y-travel 450 mm z-travel 400 mm control iTNC 530 Heidenhain turning speed range - main spindle max. 14.000 min/-1 power capacity - main spindel 18,9 / 14 kW max. Torque 100 / 74 Nm tool taper HSK A 63 table surface area 630 x 500 mm max. table load 200 kg Swivel range -110 / +5 ° rotation range 360 ° T-slots 7x 14 x 63 mm number of toolpositions 30 pos. tool taper HSK A 63 max. tool weight 6 kg max. tool diameter 80 mm max. tool-dia with free toolbox 130 mm max. tool length 300 mm rapid traverse 24 m/min Feed force 4,5 kN feed speeds 1 - 24.000 mm/min total power requirement 26 kVA weight of the machine ca. 5,0 t dimensions of the machine ca. 3,5 x 3,5 x 2,8 m CNC - Milling Machine Universal DMG DECKEL MAHO - DMU 50 New Design - 5 Axis (3+2) - swivable rotary table - only 1.943 Spindle hours Nwjdpfx Aheydqnrs Hsb

Condition: used, Year of construction: 2008, x-travel 630 mm y-travel 560 mm z-travel 560 mm control iTNC 530 Heidenhain turning speed range - main spindle max. 18.000 min/-1 power capacity - main spindel 10 / 15 kW max. Torque 130 / 87 Nm tool taper HSK-A63 swivellable NC: ° table surface area 1.000 x 600 mm T-slots 9x 14 x H7 max. table load 700 kg number of toolpositions 60 pos. tool taper HSK-A63 total power requirement 49,7 kVA weight of the machine ca. ca. 11,0 t dimensions of the machine ca. 4,5 x 4,5 x 3,5 m CNC - MachiningCenter Universal DECKEL MAHO - DMU 60 monoBLOCK - 4 axes (+ NC dividing head) - Swivel-Millinghead Nedpsx A H Rljfx Ah Hjwb

Condition: good (used), Year of construction: 2004, functionality: fully functional, Technical details x-travel 620 mm y-travel 420 mm z-travel 400 mm Control Heidenhain TNC 410M table surface area 800 x 400 mm tool taper ISO 40 spindle turning speed - stepless 50 - 4000 U/min main drive motor 5,5 kW weight of the machine ca. 2,1 t Additional information * CNC control HEIDENHAIN TNC 410M * Coolant equipment * Machine lamp Nsdpfeydmu Uex Ah Hjwb

Condition: good (used), Year of construction: 2011, functionality: fully functional, Technical details x-travel 1600 mm y-travel 1250 mm z-travel 1600 mm B-axis (table) 360.000 x 0,001° deg milling-head swivable +/- (HV) 360.000° deg pallet size: 1000 x 800 mm table load 3000 kg tool taper SK 50-B spindle turning speed range max. 8000 U/min transmission ratio 2 spindle drive (100/40 % ED) 37/50 kW feeds x/y/z -stepless 30000 mm/min total power requirement 100 kVA dimensions of the machine ca. 11555 x 7998 x 5050 mm Additional information Universal machining center 5 axes simultaneously Original purchase price: EUR 1.295.000,- First machine installation in September 2011. A geometry measurement report (dated 30. August 2025) is available. Equipment: CNC-control Siemens 840D Solution Line Separate handheld control unit, wired, Siemens HT-2 2-station pallet changer with safety light barrier 330-position tool changer (max. tool length 600 mm) with 2nd Siemens 840 D control panel Tool taper cleaning system Special cabin with oil mist extraction system Coolant tank 3.300 liters, pump pressure 4 bar/50 bar (Q1/Q2) Nwjdpfx Aoydmkpeh Hob Chip conveyor Workpiece measuring probe Manual books Spare part: New ball screw. Note: The machine will be sold without tool holders, tools, and clamping devices.

Condition: good (used), Year of construction: 2004, functionality: fully functional, Technical details x-travel 800 mm y-travel 1000 mm z-travel 655 mm tool taper ISO 40 spindle turning speed range 0 - 15000 U/min feed range 10000 mm/min rapid traverse 30 m/min power capacity (100/40% ED) 18/24 kW dimensions of machine 5000 x 2400 x 3150 mm total power requirement 40 kW weight of the machine ca. 10,5 t Additional information * CNC-control Heidenhain iTNC 530 * Number of Controlled Axes: 5 + spindle * NC-swivel-type rotary table, diameter 800 mm - Workpiece weight in clamped horizontal position 1000 kg Nwjdpfxoydmd Ns Ah Hsb - Positioning mode for both axes 600 kg (upper 30 deg. 500 kg) - 4-5 axes simultaneous mode 400 kg - Swivel range 45 deg. to the work spindle, 25 deg. away from the work spindle * 60-Position Tool Changer * Direct Measuring System, Resolution 0.001 mm * Coolant System (no coolant through spindle) * Chip Conveyor