Used Lofema Cup Grinding Machine for sale (66,229)

Condition: used, Year of construction: 1995, grinding diameter 350 mm grinding length 1000 mm centre height 175 mm Teilüberholte Maschine mit Messprotokoll nach Neumaschinentoleranz Nsdsyatx Sspfx Af Sjwl NEUE Steuerung Eckelmann ENC mit BEMA Schleifsoftware KEL-ASSIST für Kelco 90 numerisch gesteuerte B-Achse Innnschleifrinrichtung Dia 80mm Schleifscheibe links Durchmesser 400mm Schleifscheibe rechts Durchmesser 300mm Innenschleifspindel HJN 828 hydraulischer Reitstock Mikroverstellung KEL SET Messsystem

Condition: used, Year of construction: 2003, grinding width 600 x 2000 mm table surface area ca. 600 x 2400 mm x-travel 2100 mm y-travel 550 mm z-travel 560 mm Nedpfx Afozxt T Eo Sjwl max. dia. of grinding wheel 400 mm weight of the machine ca. ca 7,8 t

Condition: excellent (used), Year of construction: 2011, operating hours: 2,352 h, functionality: fully functional, total width: 2,024 mm, total length: 2,670 mm, total height: 1,800 mm, distance between centers: 650 mm, type of input current: three-phase, grinding spindle motor power: 7,500 W, overall weight: 4,000 kg, input voltage: 400 V, The machine is equipped with the following spindles: - External grinding, 7.5 kW - Thread grinding, including grinding cycles, 7.5 kW - Internal grinding spindle, Fischer, 60,000 rpm Automatic B-axis for positioning the grinding spindles. C-axis on the workpiece spindle. Direct measurement for the X and Z axes. Measuring workpiece and tool probe with an automatic cycle. Sensitron on the workpiece spindle. Nsdpfxsz Eb Tqe Af Sjwl The machine is in very good condition and has been used sparingly. Further information is available in the attached PDF files. Direct sale to end-users only. W-Technology s.r.o. Polní 8 79201 Bruntál Czech Republic

Condition: excellent (used), Year of construction: 2015, Glass thickness: Adjustable from 3 to 28 mm Max. sheet dimensions: Up to 2000 x 3000 mm Power consumption: Approx. 13.8 kW This 8-spindle machine is well-maintained and in good condition. Approx. 15,000 m run. Nwodpfxez Ekcbj Af Sol Last service in fall 2025. Accessories: Water tank, pump, and spare parts. Dimensions: Width: 6,500 mm Depth: 1,600 mm Height: 2,600 mm Weight: 3,200 kg Condition: Very good, second-hand

Condition: used, Year of construction: 1973, Technical details: grinding length: 400 mm Nwjdpfexu Dv Aex Af Ssl grinding width: 200 mm workpiece height: 300 mm dimensions of grinding wheel: 275 - 315 mm magnetic plate size: 400 x 200 mm max. table load: 200 kg weight of the machine ca.: 1,6 t dimension machine xH: 1,55 x 1,45 x 2,20 m

Condition: used, surface grinding machine Nwjdez Dubrjpfx Af Sjl

Condition: good (used), Cylindrical grinding machine, external cylindrical grinding machine, internal cylindrical grinding machine, centering grinding machine, center grinding machine -Max. shaft diameter: 320 mm -Max. grinding length: 345 mm -Chuck size: Ø 133 mm -Dimensions: 1925/1135/H1755 mm -Weight: 1592 kg -functionally tested Nwsdpfx Afsduiw Aj Ssl

Condition: used, Year of construction: 2006, Glass edging and grinding machine Njdpsxvcq Isfx Af Sowl

Condition: good (used), Year of construction: 1975, Table clamping surface 1100 x 300 mm Maximum grinding length 700 mm Maximum grinding width 350 mm Table traverse movement 300 mm Hydraulic table longitudinal movement 770 mm Maximum distance from table to spindle center 575 mm Table height above floor 1000 mm Dimensions of grinding wheel 300 / 76 x 50 mm Speed 1400/2800 rpm Automatic traverse feed 2 – 65 mm/stroke Table speed, infinitely variable 2 – 30 m/min Grinding spindle motor 4 kW Machine dimensions L x W x H approx. 2100 x 1600 x 1950 mm Control cabinet dimensions L x W x H approx. 1200 x 600 x 1700 mm Nodpfx Afsz Er R To Sewl Machine weight 2700 kg Accessories / Special features: • Infinitely variable speed control of the grinding wheel • Electro-magnetic clamping plate L x W 600 x 250 mm • Motorized up and down movement of the grinding head • Truing device • Grinding wheel flange with grinding stone • Coolant system with pump (in-house design) Siegfried Volz Machine Tools Rüschebrinkstr. 151-153 D - 44143 Dortmund - Wambel / Germany

Condition: good (used), grinding length: 400 mm, grinding width: 150 mm, Table length 400 mm Table width 150 mm Grinding length 400 mm Grinding width 150 mm Design: hydraulic Max. distance from table to spindle center line 350 mm Table speeds: continuously variable from 0.00 m/min Nwsdpfx Afsvga Sus Sjl up to 0.0 m/min Automatic vertical feed: from 0.000 mm up to 0.013 mm Diameter of grinding wheel 00 mm Width of the grinding wheel 16 mm Grinding wheel speeds: from 800 rpm Voltage 50 Hz 3x 380 Volt Grinding spindle motor 0.30 HP Machine weight approximately 900 kg Overall dimensions of the machine: Length 1300 mm Width 1000 mm Height 1500 mm

Condition: used, Universal external and internal cylindrical grinding machine CINCINNATI - MSO, Type R75 Serial No. 27782, Year of manufacture 1976 Center distance max. 805 mm Workpiece grinding length max. 800 mm Center height 130 mm Swinging diameter max. 250 mm Workpiece grinding diameter max. 250 mm Workpiece weight between centers max. 75 kg Workpiece weight in chuck max. 20 kg Workpiece spindle speed 50 - 390 rpm Tailstock internal taper MK 5 Tailstock short taper flange DIN 55027, Size 5, Ø 82 mm Nwedpfx Afjz Ek Sij Sel Tailstock spindle bore 38 mm Headstock internal taper MK 3 Grinding wheel diameter max. 300 mm Grinding wheel width max. 40 mm Grinding wheel peripheral speed 30 m/sec Tailstock quick traverse 50 mm Automatic tailstock feed 0.005 to 0.03 mm Manual feed 0.0025 mm Hydraulic table movement 0.05 - 6 m/min Motor power grinding spindle 3 kW Motor power workpiece spindle 0.75 kW Motor power internal grinding attachment 0.75 kW Power connection 380 Volt, 50 Hz - Feed and plunge system, manual or automatic feed - Grinding spindle swivels +/- 90° - Workpiece spindle swivels 0 to 90° - Table tilt for taper grinding up to 10° - Counter support / quill for the workpiece spindle with internal taper MK 3 - Internal grinding spindle missing, internal grinding attachment for swiveling - Coolant system adjacent - 1 diamond grinding wheel dresser - 3 grinding wheels with grinding wheel arbors - 1 grinding wheel without grinding wheel arbor - 1 grinding wheel puller - 1 reducing sleeve - 3 centering pins - Several drive dogs - Operating manual with electrical diagram Space requirement L x W x H 2350 x 2000 x 1600 mm Weight 2500 kg Good condition

Condition: used, grinding diameter 350 mm grinding length 1500 mm centre height 175 mm grinding wheel diameter 400 mm grinding wheel width 50 mm bore 127 mm MK5 work piece spindle speed 20-400 U/min grinding head swivelling 360 ° grinding spindle head - swivable 180 + - ° grinding spindle speed 1500,1700,2200 U/min 0-40 mm/Ø 0-40 mm/Ø ±6,5 ° longitudinal feed of the table 1530 mm table speeds 0,02-6 m/min 130 kg 130 inkl. Spannung kg cross travel max. 270 mm 80 mm tailstock quill taper MT 3 quill travel 30 mm total power requirement 6,5 kW weight of the machine ca. 3,05 t Nwodpfsuxftrjx Af Sjl dimensions of the machine ca. 4 x 2 m Overhauled according to Kellenberger guidelines including new, modern and future-proof control system. Photo of machine already delivered with special options -Operation via the touch panel is extremely simple. -The symbols on the control panel are practically identical to the original original control system, so there is no need for familiarisation. -Diagnostic function with display of PLC messages and digital I/O -Dressing function can be extended or changed at the customer's request. -Orientated spindle stop of the workpiece spindle possible on request. -New maximum infeed of 40 mm can be extended on request. -Digital display in 2 axes. Resolution x-axis 0.5my Options: -Encoder with digital display in the workpiece headstock -Rotary encoder with digital display in the grinding headstock (no height adjustment with spindle possible) with spindle possible) -New stable internal grinding device diameter 80mm or 100mm with height adjustment. -Increase of the centre height to max. 225mm -Speed control for the grinding spindle Included: -Operating tool -Clamping tube for chuck Further accessories on request. The x-axis of the machine has an electronically controlled infeed system with stepper motor drive. Hydraulic longitudinal and rapid traverse table movement. Versatile application in production for external cylindrical and internal internal grinding or for external, face and internal grinding in one clamping clamping of individual parts. Possible options: -Semi-automatic dressing cycles for external and internal grinding -automatic dressing compensation. -Measuring control

Condition: used, Year of construction: 1993, Technical details: rotary table diameter: 2x700 mm grinding height: 200 mm grinding head - power requirement: 15 kW max. dia. of grinding wheel: 400 mm grinding spindle speed: 1400-2800 stufenlos /continous U/min automatic feeds: 0,001-0,02 weight of tools max.: 650 kg table speed: 5-10 m/min rotary table revolutions per minute : 5-10 stufenlos U/min rotary table: Querbewg. 0,2...10 m/min total power requirement: 49 kW weight of the machine ca.: ca. 12,0 t dimension machine xH: 6,0x3,0x2,8 m dimensions electric cabinet LxWxH: 2,0x0,55x2,2 m ROTARY TABLE SURFACE GRINDING MACHINE - 2 magnetic rotary tables each Ø=700mm - diamond roller dressing device - without coolant unit Nedpfxou Ngp Ne Af Sswl i.D. *

Condition: used, Year of construction: 1981, Technical details: grinding diameter: 240 mm Nwsdpfx Afsu Ng Avj Sel grinding length: 700 mm centre height: 125 mm table length: 1525 (schwenkbar) mm distance grinding spindle - table min./max.: 225/410 mm rpm speed range - grinding wheel: 1590 U/min grinding wheel dia. (unused wheel): 600 mm grinding wheel dia. (used wheel): 450 mm cutting speed: 50 m/s total power requirement: 13 kW weight of the machine ca.: 5,5 t space requirements of the machine approx.: L:2,8xB:2,2xH:1,8 m Cylindrical grinding machine, semi-automatic operation - grinding spindle head -adjustment 185mm - grinding spindle head-infeed 0,001-0,05 mm/min continuous - rotation workpiece 50-500 rpm continuous machine is equipped: - sleeve with hydr. retraction - cooling device - trueing device - grinding wheel balancing - transverse delivering device for grinding spindle head - hydr. adjustment of grinding table. Upper table swivable. Documentation i.D. *

Condition: used, Year of construction: 1961, Technical details: grinding length: 600 mm grinding width: 200 mm workpiece height: 270 mm grinding length: mit Magnet: 500 mm Distance Spindlecenter - clamping surface area, min:: 350 mm grinding spindle speed: 1000...4700 U/min table surface area: 720 x 200 mm table load capacity: 60 kp Njdpsu Ngg Uefx Af Sswl magnetic plate size: 455 x 180 (Gleichstrom) mm magnetic-table: vertical kippen 90° längs Stück total power requirement: 2,0 (2,7 PS) kW weight of the machine ca.: 1600 + 176 kg Gleichrichter kg dimension machine xH: 1,4 x 1,8 x 1,7 m transport measurements machine: 1,4 x 1,8 x 1,6 m dimensions electric cabinet: L: 850 x B: 450 x H: 1.100 mm dimensions of grinding wheel: Ø 225 x 20 x Bohrung Ø 51 mm mm The magnetic plate (24V) is cooled. Grinding spindle: The grinding wheel infeed is electric, vertical 270mm, infeed z-axis 0,002 mm to unlimited inching infeed 0,001 - 0,010mm Peripheral speed max 35 m/sec. allowed equipped with coolant tank, pump and magnetic separator, as well as grinding wheel - size Ø 152 x 14mm plus various accessories (in the cabinet) like some grinding wheels and balancing flange The machine is pre-equipped for an exhaust system. *

Condition: good (used), Year of construction: 2008, functionality: fully functional, Technical specifications – Geibel & Hotz FS 840 SD Max. grinding area (mm) 800 x 400 x 375 Travel in X-axis (mm) 800 Travel in Y-axis (mm) 400 Travel in Z-axis (mm) 375 Clamping surface (magnetic) (mm) 800 x 400 Grinding wheel (mm) 300 x 50 x 76.2 Power of grinding spindle motor (kW) 3.7 Grinding spindle speed (rpm) 1400 Manufacturer Geibel & Hotz Year of manufacture 2008 Control type Cycle-controlled Total power consumption (kW) 12 kW Space requirement (mm) 3600 x 2750 x 2470 Weight (kg) 2700 Condition Used Nwedpoz Ebvfjfx Af Sjl

Condition: used, REISHAUER US is a Thread grinding machine of high precision, engineered for superior accuracy and reliability. Capacities: grinding length 450 mm; clamping 1055 mm; max Ø 250 mm; thread Ø 2–250 mm; spindle bore 45 mm; weight on centres 200 kg; pitch ≤100 mm; angles ±40°; module ≤10; wheels Ø280–350 mm, width 4–40 mm. Specs: wheel speeds 6 steps 1700–2540 rpm; work spindle 27 steps up to 160 rpm; 3×380 V 50 Hz; grinding spindle 4 kW; total 15 kVA; machine ≈4700 kg; footprint 3300×1930×1800 mm. Accessories: coolant, wheel set, flanges, gear set, centers, oil-mist extractor. Achieves tight tolerances; suitable for automotive, aerospace, watchmaking, machine tools, medical. Nwodpfxjz Dbh Eo Af Sel

Condition: excellent (used), Year of construction: 2023, width of the strips 75.0 mm band length 2000 mm band speed 30.0 m/sek grinding width 500 Plantisch mm suction capacity 630 m³/h total power requirement 3.75 kW weight of the machine ca. 90.0 kg range L-W-H 1100 x 550 x 1035 mm current new price incl. accessories approx. 2.500 euros incl. replacement sanding belts special price on request Equipment : - High quality construction - Drive roller is crowned - This means that the sanding belt is automatically centered on the roller - Fully vulcanized contact roller for maximum service life and smooth running - Tool-free and therefore quick, uncomplicated change of the sanding belt - Stepless height adjustment - for optimum adjustment of the belt sander to the user Nwsdpfxey Erxvo Af Sel - Freely adjustable metal fence - for optimum and safe guidance of workpieces when Use of the large surface sanding area - Belt speed optimized by design - to prevent the workpiece from burning during processing can be excluded as far as possible - Suction unit equipped with robust and flexible suction hoses - Motor protection switch with CEE collar connector incl. phase inverter - Motor brake - Incl. sanding belt grain 60 - Dust bag

Condition: like new (used), Year of construction: 2024, operating hours: 100 h, functionality: fully functional, machine/vehicle number: 90L0865829G_00, overall weight: 1,000 kg, input frequency: 50 Hz, type of input current: AC, input voltage: 400 V, The CMS Proxima is an automatic horizontal edging machine (dry edging machine) from CMS Glass Technology for processing glass edges. Processing length: The maximum working length per cycle is approximately 2.6 to 2.7 meters (larger panes can be accommodated). Nwjdpjz E Axzsfx Af Ssl Glass thickness: Can process glass from approximately 4 to 19 mm. It can be operated either as a stand-alone unit (with a simple setup table) or in combination with tilting float cutting tables or laminated safety glass (VSG) cutting tables.

Condition: used, grinding diameter 250,350,450 mm grinding length 1000 mm Njdpot Ii Nujfx Af Sswl centre height 125,175,225 mm grinding wheel diameter 400 mm grinding wheel width 50 mm bore 127 mm MK5 work piece spindle speed 20-400 U/min grinding head swivelling 360 ° grinding spindle head - swivable 180 + - ° grinding spindle speed 1500,1700,2200 U/min 0,001-0,030 mm/Ø 0-0,95 mm/Ø ±8 ° longitudinal feed of the table 1300 mm table speeds 0,02-6 m/min 130 kg 130 inkl. Spannugkg kg 70 mm total power requirement 6,5 kW weight of the machine ca. 2,5 t dimensions of the machine ca. 4,2 x 2,0 m As the world’s leading company in Kellenberger overhaul and retrofit we are not only able to deliver machines in a quality similar to a new machine and with warranty, but we can also offer you the service for your machines. Geometrically overhauled with new paint and original electrics. Foto of a 600U which we already have delivered. -Digital display in 2 axes. Resolution of x-Achse 0,5my Options: -Encoder with digital display in workpiece spindle head -Encoder with digital display in grinding spindle head (Height adjustment with spindle not possible) -New stable internal grinding diameter 80mm oder 100mm with height-adjustment. -Increase the center heigh to max. 225mm -Speed control of the grinding spindle Including:: -Adjustment tool -Draw tube for chucks other accessories on reqeust Die Werkzeugmaschine entspricht zum derzeitigen Zeitpunkt nicht den grundlegenden Sicherheits- und Schutzanforderungen wie in der BetrSichV 2015 genannt. Eine Anhebung des erforderlichen Mindest-Schutzzieles ist mittels einer Gefährdungsbeurteilung nach BetrSichV zu ermitteln.

Year of construction: 1988, condition: used, Tschudin cylindrical grinding machine. Nodpfx Aez Dpzmjf Sjwl

Condition: excellent (used), Year of construction: 1991, functionality: fully functional, We have two CSEPEL FKP326-10 gear grinding machine as follows. 1)1991 (Changed new PLC dated on Oct. 2024) 2)1989 Included all the auxiliary tools and accessories. They are well in operation at site. Thank you very much. Best Wishes, Steve Bae Nwedpfoz Am Nzex Af Sol

Condition: used, grinding diameter 350,450 mm grinding length 600 mm centre height 175,225 mm grinding wheel diameter 400 mm grinding wheel width 50 mm bore 127 mm MK5 work piece spindle speed 20-400 U/min grinding head swivelling 360 ° grinding spindle head - swivable 180 + - ° grinding spindle speed 1500,1700,2200 U/min 0,001-0,030 mm/Ø 0-0,95 mm/Ø ±10 ° longitudinal feed of the table 900 mm table speeds 0,02-6 m/min 130 kg 130 inkl. Spannugkg kg 70 mm total power requirement 6,5 kW weight of the machine ca. 2,2 t dimensions of the machine ca. 3,1 x 2,0 m As the world’s leading company in Kellenberger overhaul and retrofit we are not only able to deliver machines in a quality similar to a new machine and with warranty, but we can also offer you the service for your machines. Foto von bereits gelieferter Maschine mit eventuell anderen Optionen. Maschine hat Zentralschmierung und Rollenführung in der Flachbahn der x-Achse sowie Luftabhebung im Schleifspindelstock serienmäßig. BEMA Standard serienmäßig: -Digitalanzeige in 2 Achsen. Auflösung x-Achse 0,5my -Drehzahlanzeige Schleifspindel -Stufenlose Drehzahl Schleifspindel 70-100% -Stufenlose Drehzahl Innenschleifspindel 70-100% -Werkstückspindelantrieb durch Drehstrommotor stufenlos regelbar über Frequenzumrichter Mögliche Optionen gegen Aufpreis: -Drehgeber mit digitaler Anzeige im Werkstückspindelstock -Drehgeber mit digitaler Anzeige im Schleifspindelstock (keine Höhenverstellung mit Spindel möglich) -Sinuslineal -Neue stabile Innenschleifvorrichtung Durchmesser 80mm oder 100mm mit Höhenjustierung. -Erhöhung der Spitzenhöhe auf max. 225mm -Drehzahlregelung für die Schleifspindel Nwedpfxod Ih D Es Af Sel Inklusive: -Bedienwerkzeug -Spannrohr für Futter Natürlich erhalten Sie auf unsere generalüberhalten Maschinen 12 Monate Gewährleistung. (Nur Anrainerstaaten) weiteres Zubehör auf Anfrage. Die Werkzeugmaschine entspricht zum derzeitigen Zeitpunkt nicht den grundlegenden Sicherheits- und Schutzanforderungen wie in der BetrSichV 2015 genannt. Eine Anhebung des erforderlichen Mindest-Schutzzieles ist mittels einer Gefährdungsbeurteilung nach BetrSichV zu ermitteln

Condition: used, grinding diameter 250,350,450 mm grinding length 1000 mm Njdpfx Aed Ih D Hof Sjwl centre height 125,175,225 mm grinding wheel diameter 400 mm grinding wheel width 50 mm bore 127 mm MK5 work piece spindle speed 20-400 U/min grinding head swivelling 360 ° grinding spindle head - swivable 180 + - ° grinding spindle speed 1500,1700,2200 U/min 0,001-0,030 mm/Ø 0-0,95 mm/Ø ±8 ° longitudinal feed of the table 1300 mm table speeds 0,02-6 m/min 130 kg 130 inkl. Spannugkg kg 70 mm total power requirement 6,5 kW weight of the machine ca. 2,5 t dimensions of the machine ca. 4,2 x 2,0 m As the world’s leading company in Kellenberger overhaul and retrofit we are not only able to deliver machines in a quality similar to a new machine and with warranty, but we can also offer you the service for your sion R: Maschine hat Zentralschmierung und Rollenführung in der Flachbahn der x-Achse sowie Luftabhebung im Schleifspindelstock. Beispielfoto einer von uns überholten 600U -Digitalanzeige in 2 Achsen. Auflösung x-Achse 0,5my Optionen: -Drehgeber mit digitaler Anzeige im Werkstückspindelstock -Drehgeber mit digitaler Anzeige im Schleifspindelstock (keine Höhenverstellung mit Spindel möglich) -Neue stabile Innenschleifvorrichtung Durchmesser 80mm oder 100mm mit Höhenjustierung. -Erhöhung der Spitzenhöhe auf max. 225mm -Drehzahlregelung für die Schleifspindel Inklusive: -Bedienwerkzeug -Spannrohr für Futter weiteres Zubehör auf Anfrage. Overhauled with geometric KELLENBERGER protocoll. Standard with: -2-axis DRO -Paper filtration Die Werkzeugmaschine entspricht zum derzeitigen Zeitpunkt nicht den grundlegenden Sicherheits- und Schutzanforderungen wie in der BetrSichV 2015 genannt. Eine Anhebung des erforderlichen Mindest-Schutzzieles ist mittels einer Gefährdungsbeurteilung nach BetrSichV zu ermitteln.

Condition: used, grinding diameter 350 mm grinding length 1000 mm centre height 175 mm grinding wheel diameter 400 mm grinding wheel width 50 mm bore 127 mm MK5 work piece spindle speed 20-400 U/min grinding head swivelling 360 ° grinding spindle head - swivable 180 + - ° grinding spindle speed 1500,1700,2200 U/min 0-9,99 mm/Ø 0-9,99 mm/Ø ±8 ° longitudinal feed of the table 1100 mm table speeds 0,02-6 m/min 130 kg cross travel max. 270 mm 130 inkl. Spannung kg 80 mm tailstock quill taper MT 3 quill travel 30 mm total power requirement 6,5 kW weight of the machine ca. 3,05 t dimensions of the machine ca. 4 x 2 m Overhauled according to Kellenberger guidelines including new, modern and future-proof control system. Photo of already delivered machine in centre distance 1000mm. -Operation via the touch panel is extremely simple. -The symbols on the control panel are practically identical to the original original control system, so there is no need for familiarisation. -Diagnostic function with display of PLC messages and digital I/O -Dressing function can be extended or changed at the customer's request. -Orientated spindle stop of the workpiece spindle possible on request. -New maximum infeed of 40 mm can be extended on request. -Digital display in 2 axes. Resolution x-axis 0.5my Options: -Encoder with digital display in the workpiece headstock -Rotary encoder with digital display in the grinding headstock (no height adjustment with spindle possible) with spindle possible) -New stable internal grinding device diameter 80mm or 100mm with height adjustment. -Increase of the centre height to max. 225mm -Speed control for the grinding spindle Included: -Operating tool -Clamping tube for chuck Further accessories on request. The x-axis of the machine has an electronically controlled infeed system with stepper motor drive. Nwodpfx Aouxfupof Sel Hydraulic longitudinal and rapid traverse table movement. Versatile application in production for external cylindrical and internal internal grinding or for external, face and internal grinding in one clamping clamping of individual parts. Possible options: -Semi-automatic dressing cycles for external and internal grinding -automatic dressing compensation. -Measuring control