Used Raskin Rt-85 for sale (8,924)

Condition: ready for operation (used), Year of construction: 2000, functionality: fully functional, stroke length: 215 mm, throat depth: 410 mm, bending force (max.): 85 t, distance between stands: 1,750 mm, working length: 2,050 mm, TECHNICAL DETAILS Press force: 85 t Bending length: 2,050 mm Distance between uprights: 1,750 mm Stroke: 215 mm Throat depth: 410 mm MACHINE DETAILS Control: DELEM Dimensions & Weight Machine dimensions: 2,700 x 2,100 x 2,400 mm Weight: 7,900 kg Lhodpfeyhmdqsx Ahtjk EQUIPMENT Two-hand operation 2 support arms Side safety doors Lasersafe Fissler Wila tool clamping Adjustable die position Crowning system Tool cabinet

Condition: new, Year of construction: 2026, functionality: fully functional, spindle speed (max.): 36,000 rpm, spindle speed (min.): 12,000 rpm, High part output | 3D CNC milling for small workpieces up to 1000 x 800 x 400 mm. > Efficient milling spindle, short throughput times and high part output: Due to the highly efficient milling spindle, the 5-axis CNC machine creates a high part output. The CNC milling machine stands for absolutely fast production processes and short throughput times. In addition, the rotary table of the CNC milling machine performs the C-axis movement, making milling even more effective. > Little space required, fast commissioning: The RT-F 1400 CNC milling machine requires little space and can be commissioned within two days. Set-up times are minimal. The CNC machine can be easily moved to another location using a forklift. > First-class contour accuracy for 3D machining with fixtures: All components, such as milling tool, spindle and the machine are matched to each other and to the desired component. A fixture from HG GRIMME SysTech can additionally influence the milling quality. Existing fixtures can be reused at any time. > Use in industry and small businesses: The CNC rotary table milling machine RT-F 1400 is particularly suitable for 3D machining of smaller components (800x1000x400mm). The CNC milling machine is used just as successfully by large industrial companies, such as the automotive industry, as it is in small businesses. > Basic version of the CNC machining center - Protective cabin with automatic gate unit, pneumatic - Swiveling, integrated control panel - High-performance CNC control NUM Flexium+ with nPad and 19'' monitor - Tool changing system with 12 places, dust-tight - Tool measurement Renishaw-TS 27 R - chip tray, vacuum pump > 365 further equipment options - example CFK package The machine can be equipped with many further options. One example is the upgrade of the machine equipment for CFRP machining. The CFRP package takes into account many safety aspects that are necessary for the processing of composite material. We offer around 365 additional options across our entire product range and can further equip the basic machine offered at any time. > Suitable materials for the 5-axis CNC rotary table milling machine 1400: plastics, composites such as CFRP, model making materials, aluminum. Further technical data Cube dimensions component - 1000 x 800 x 400 mm (+162 mm substructure) Travels X/Y and Z - X/Y and Z: 1,040 x 1,400 mm x 725 mm Travels of rotary axes A and C - Rotary axis C (table) ± 1,080°. - Swivel axis A, standard tool spindle with tool changing system ± 110°. Speeds - Rapid traverse linear axes X/Y/Z 40/40/30 m/min - Rapid traverse rotary axes A/C 14,000°/18,000° m/min Accuracies - Positioning accuracy ± 0.040 mm - Repeat accuracy ± 0.035 mm Machine rotary table - ø 800 mm Table load - approx. 200 kg Milling spindle - High-frequency milling spindle 9 kW (S6) - High frequency milling spindle 8 kW (S1) - speed 36.000 rpm - Tool holder HSK 40 E Machine weight - approx. 3000 kg Already included special equipment - Head suction for floating dust and chips Lodpfjx S Etmox Ahtehk - Interior with perforated footboards - interior lighting - Ethernet and remote maintenance - 3D spline - Connection T-Box (nPad) (subject to change without notice)

Condition: new, Year of construction: 2026, machine/vehicle number: 20251217010, Field of application: Construction Empty weight: 344 kg Generator capacity: 85 kVA Ledpfx Ahewp Aarotjhk Dimensions of cargo space: 86 x 46 x 53 cm CE mark: yes Frequency: 50 Voltage: 400 Production country: CN Please contact Team DPX for more information

Condition: used, mileage: 5,52,546 km, power: 353 kW (479.95 HP), first registration: 04/2015, fuel type: diesel, tire size: 385/65R22.5, axle configuration: 8x2, wheelbase: 5,550 mm, fuel: diesel, color: red, driver cabin: sleeper cab, gearing type: automatic, emission class: euro6, suspension: air, total length: 8,200 mm, total width: 2,550 mm, Year of construction: 2015, Equipment: ABS, AdBlue, air conditioning, central locking, cruise control, differential lock, electric window regulation, fridge, parking heater, seat heater, traction control, trailer coupling, = Additional Options and Equipment = Lsdpfxew Dr H Rs Ahtehk - Differential lock - Remote central locking - Lift axle - Towing jaw (Maulkupplung) - PTO (Power Take-Off) - Radio - Disc brakes - Sun visor - Spotlights - Auxiliary heater - Toolbox = Remarks = HMF 8520 OK6 Scanreco radio remote control. 4 x hydraulic outriggers. 6 x hydraulic extensions. Winch: 2,500 kg. 4.48 m – 16,030 kg 6.33 m – 11,100 kg 8.23 m – 8,310 kg 10.23 m – 6,520 kg 12.33 m – 5,300 kg 14.51 m – 4,440 kg 16.75 m – 3,820 kg Adjustable fifth wheel. Stainless steel toolboxes. = Further Information = Technical Information Number of cylinders: 6 Axle Configuration Brakes: Disc brakes Suspension: Air suspension Front axle 1: Tyre size: 385/65R22.5; Steering; Tyre tread left: 70%; Tyre tread right: 70% Front axle 2: Tyre size: 385/65R22.5; Steering; Tyre tread left: 70%; Tyre tread right: 70% Rear axle: Tyre size: 315/70R22.5; Twin tires; Tyre tread left inner: 20%; Tyre tread left outer: 20%; Tyre tread right inner: 20%; Tyre tread right outer: 20% Front axle 3: Tyre size: 385/55R22.5; Steering; Tyre tread left: 60%; Tyre tread right: 60% Weights Kerb weight: 25,390 kg Payload: 11,110 kg Gross vehicle weight: 36,500 kg Functional Crane: HMF Financial Information Price: On request Identification Model number: TGX 37.480 8x2-6 / HMF 85 t/m CR = Company Information = ALL PRICES ARE NET FOR EXPORT. Joris Versteijnen (NL-DE-GB) Wouter Greutink (NL-DE-GB-ES-IT) We speak Russian. We strive to provide accurate information, but no rights can be derived from the texts provided.

Condition: reconditioned (used), Year of construction: 1998, functionality: fully functional, machine/vehicle number: 265134, warranty duration: 6 months, year of last overhaul: 2026, Equipment: type plate available, Multimatic MUS 6 WP Bakery Divider. Fully automatic machine for dividing and rounding dough. Designed for doughs with a yield (TA) of 148-160. Key features: - Capacity: up to 12,000 pieces/hour, - Weight range: 28 - 85 g, - Number of rows: 6, - Hydraulic system for the main piston, - Condition: as new (after complete overhaul), - Hopper volume: 50 l, - Round product, Lhsdpfx Ahjuv Hrwstsk - Constructed of stainless steel.

Condition: used, mileage: 1,001 km, gearing type: other, fuel type: diesel, first registration: 01/1995, Year of construction: 1995, driver cabin: other, Vehicle location: Bovenden. Lhjdpfji Rqnpox Ahtek Type: Joint cutter with Honda GX390 engine, 13.0. ACCESSORY INFORMATION PROVIDED WITHOUT GUARANTEE. Subject to changes, prior sale and errors!

Condition: new, Cluster tool C/D/E station thick turret punch tool for Amada, Lvd Ledpfx Aheiq Dmmotohk Original style punch compatiable for Amada/Mate guide holder quick adjustable style compatiable for Mate/Wilson 90 guide holder

Condition: excellent (used), Year of construction: 2011, functionality: fully functional, machine/vehicle number: 23900101, Equipment: type plate available, PACKAGING MACHINE FOR FOOD PRODUCTS SUCH AS MEAT, COLD CUTS, CHEESE, IN FILM PACKAGING UNDER VACUUM OR IN INERT GAS. THE MACHINE HAS FIVE FORMATS. I HAVE A LARGE SET OF SPARE PARTS FOR THE MACHINE: KNIVES, SEALS, VALVES, ETC. Ljdpfx Ahow Emh Ejtshk

Condition: new, functionality: fully functional, power: 200 kW (271.92 HP), fuel type: electric, color: other, overall weight: 14,000 kg, Year of construction: 2026, *All of our products are made with care and covered for 1 year warranty! *Installation and Operator Training FREE VSI Vertical shaft impact crushers are used to obtain fine sand and fine gravel from the hardest with a high degree of abrasive materials such as basalt, granite, gabbro, riverstone etc. Lsdpfxjzlr R Ao Ahtehk This type of crushers acting as tertiary crushers in facilities with it’s high cubic ratio and fine product. These high-speed crushers are manufactured in two different combinations as open rotor and closed rotor. Vertical shaft impact crushers (VSI) are designed with a unique rock-on-rock crushing principle, which significantly reduces the wear costs while offering superior cubical shape for the best quality fine aggregate production. The fact that it reduces their service requirements and time, and to increase their crushing performance with their low investment costs. General Specifitions and Features: - Fine product, low wear cost, cubic shape, application flexibility and maintainability. - Rotor and crushing chute with stress relieved welding - Inner surfaces of the crusher is coated with wear resistant lining plates - Hydraulic opening cap -Automatic Lubrication system • Model: FABO VSI-900 • Type: Vertical Shaft Impact Crusher Closed rotor • Capacity: 100-300 tph • Max Feeding: 45 mm • Rotor Size: Ø 900 mm • Speed: 50-70 m/s • Motor: Heavy duty GAMAK, 2 X 160-200 kW Bearings: Heavy duty SKF-FAG • Weight: 14000 kg • Including chassis, motor and safety guards. FOR FURTHER INFORMATION PLEASE FEEL FREE TO CALL US!!!

Condition: used, Year of construction: 2026, total length: 7,320 mm, Articulated telescopic work platform Magni MHAB18RT Drive Diesel Ledpfjy Tp Nbox Ahtehk Year built 2026 Work height (mm) 18,110

Condition: used, Year of construction: 2022, total length: 9,800 mm, - Max. Arbeitshöhe 22,21 m - Max. Höhe Arbeitskorb 18,28 m - Gelenkpunkt 8,13 m - Max. Reichweite 10,69 m - Negative Höhe 1,263 m - Negative Reichweite 11,30 m - Max. Tragkraft 230 kg - Max. Steigfähigkeit (eingefahren) 30 % - Max. Neigung X -5° / Y -5° - Max. Windgeschwindigkeit 12,5 m/s - Wenderadius (außen) 2,57 m - Wenderadius (innen) 1,56 m - Drehbereich Oberwagen (endlos) 360° - Vertikale JIB-Drehung +70°/-60° - Breite Arbeitskorb 0,79 m - Länge Arbeitskorb 1,83 m - Drehung Arbeitskorb 180° (+/-90°) - Geschwindigkeit (eingefahren) 6,1 km/h - Geschwindigkeit (ausgefahren) 1,1 km/h - Reifen 315/55 D20 - Hydrauliköltank 67 l - Batterietyp Bleibatterie - Batteriekapazität 24x2 V/375 Ah - Ladegerät 48 V/60 A - Antrieb Hydrostatisch - Vordere Pendelachse für höhere Stabilität auf allen Untergründen - Selbstsperrdifferenzial - Steckdose am Arbeitskorb - Sicherer Betrieb bis 12,5 m/s Windgeschwindigkeit - Integrierte Diagnoseanzeige mit CAN-Bustechnik - Hoher Grad an Baugleichheit im Sortiment - Drehbereich 360° - Allradantrieb - 4 Lenkräder - CAN-BUS - Große Öffnungsweite für einfachere Instandhaltung - Hupe - Betriebsstundenzähler - Proportionalsteuerung - Rundumleuchte - Non-Marking-Reifen - Elektrische Sicherheitspumpe - Not-Halt-Taste - Fahrsignal Lodpfozrp Ilsx Ahtshk - Notabsenkung - Borddiagnose - Fahrbewegung zulässig bei maximaler Hubhöhe - Hydraulische Plattformdrehung

Condition: used, Year of construction: 2026, load capacity: 8,000 kg, lifting height: 51,000 mm, total length: 11,520 mm, Rotating forklift Lhodpfx Aoy Tb Hfjhtek Magni RTH 8.51 Drive Diesel Year built 2026 Lifting height (mm) 51,000 Lifting weight (kg) 8,000

Condition: new, empty load weight: 2,980 kg, maximum load weight: 10,020 kg, overall weight: 13,000 kg, axle configuration: 2 axles, loading space length: 5,110 mm, loading space width: 2,430 mm, suspension: steel, color: other, gearing type: other, driver cabin: other, emission class: none, Equipment: ABS, compressed air brake, Three-way tipper, loading height approx. 940 mm, front wall - foldable for overloading, central locking for side and rear drop sides, automatic rear wall opening when tipping backwards, side drop sides swinging and foldable, side drop sides with spring relief, bridge floor made of fine-grained steel 4 mm, 8 x strong lashing eyes recessed in the floor, 5-stage hard chrome-plated three-sided tipping cylinder, tipping angle: 50 degree tipping angle to the rear and 45 degree tipping angle to the side, infinitely height-adjustable drawbar, rear stanchions can be plugged in, geared support winch with load and fast gear, front, mounting shaft for two aluminum drive-on ramps integrated in the chassis, lockable ramp shaft (privacy screen), contour marking according to ECE R 048 regulation, , -- Misprints, errors and omissions excepted, sample images --, More data under: !, More Details: ! Ledpfx Ajzr Sfashtjhk

Condition: new, functionality: fully functional, Year of construction: 2025, operating hours: 15 h, load capacity: 6,000 kg, lifting height: 26,000 mm, fuel type: diesel, mast type: telescopic, construction height: 3,100 mm, power: 115 kW (156.36 HP), fork length: 1,200 mm, empty load weight: 18,000 kg, total length: 8,080 mm, drive type: Diesel, construction width: 2,500 mm, Rotating Telehandler Mast type: Telescopic Transmission: Hydrostatic Speed class: 20 Condition: New machine Technical condition: New Front tire type: Pneumatic Front tire size: 18 - 22 Front tire condition: 80 - 100% Lhjdpfx Aowbw Hkehtsk Rear tire type: Pneumatic Rear tire size: 18 - 22 Rear tire condition: 80 - 100% Description: Thanks to its 3-in-1 design (telescopic handler, crane, and aerial work platform), the MRT 2660 is a versatile tool for your handling operations. The MRT 2660 has a lifting capacity of up to 6 tonnes, and its pentagonal boom profile combined with exceptional 360° visibility provides highly precise load control. With 360° continuous rotation, you can perform multiple tasks without needing to reposition the machine. It can be operated either on wheels or stabilizers, offering a larger footprint for safe working conditions. The MRT 2660 is intelligent, ergonomic, and comfortable, making it ideal for use in construction and industrial applications. This is a powerful and precise tool you won’t want to do without! A variety of attachments, such as a personnel basket, winch, or bucket, are available for this telehandler. Third hydraulic valve, rear work lights, front work lights, heater, full cab, air conditioning, radio remote control.

Condition: refurbished (used), Year of construction: 2010, Wittmann W853 Linear Z=4000mm , payload: 41,5 kg Number of axis: 3 X: 1500 mm Y: 2600 mm Z: 4000 mm \+ C axis pneumatic Ljdpswnfmfefx Ahtehk Reach: 4000 mm Payload: 41 kg Robot has NEW CPU + batteries , fully tested by Wittmann technician in our showroom.

Condition: good (used), Year of construction: 2004, Engel INSERT 200H/40 Control: CC100 Condition: fully funtional Clamping force: 400 kN Opening stroke: 300 mm Lhjdpfx Astrhv Sshtsk Ejector force: 20 kN Ejector travel: 100 mm Opening max. : 570 Opening min. : 270 Platen size: 590x340 mm Screw: 25 mm Screw length: 140 mm Injection volume: 69 cm3 Injection pressure: 2090 bar Weight: 5400 kg Pump drive power: 15 kW

Condition: new, empty load weight: 2,980 kg, maximum load weight: 7,520 kg, overall weight: 10,500 kg, axle configuration: 2 axles, loading space length: 6,280 mm, loading space width: 2,480 mm, suspension: steel, tire size: 245 / 70 R 17,5, wheelbase: 990 mm, color: other, gearing type: other, front tire size: 245 / 70 R 17,5, rear tire size: 245 / 70 R 17,5, driver cabin: other, emission class: none, fuel: biodiesel, Equipment: ABS, compressed air brake, each ramp approx. 2,700 mm long x 560 mm wide, ramps with gratings, loading height: 840 mm, 12 lashing eyes each 2.5 t, 8 x lashing eyes each 6 t, steel drop sides, foldable and removable, wooden planks 50 mm, loading area rear beveled, loading area width inside 2.480 mm, rear stanchion removable, front for through-loading, , Also available in 5,300 mm loading area length!!!, , Rental price from 500 ¤ , , -- Misprints, errors and omissions excepted, sample pictures --, More data under: !, More Details: ! Lhsdpjztd Rdofx Ahtjk

Condition: used, Year of construction: 2021, load capacity: 5,500 kg, lifting height: 31,600 mm, total length: 9,700 mm, Rotating forklift Manitou MRT 3255 Lodpfeztghxjx Ahtshk Drive Diesel Year built 2021 Lifting height (mm) 31,600 Lifting weight (kg) 5,500

Condition: new, Year of construction: 2026, load capacity: 6,000 kg, lifting height: 29,900 mm, total length: 9,140 mm, Rotating forklift Manitou MRT 3060 Drive Diesel Year built 2026 Lifting height (mm) 29,900 Ledpfx Ahoztggujtjhk Lifting weight (kg) 6,000

Condition: new, empty load weight: 2,980 kg, maximum load weight: 7,520 kg, overall weight: 10,500 kg, axle configuration: 2 axles, loading space length: 6,280 mm, loading space width: 2,480 mm, suspension: steel, tire size: 245 / 70 R 17,5, wheelbase: 990 mm, color: other, gearing type: other, front tire size: 245 / 70 R 17,5, rear tire size: 245 / 70 R 17,5, driver cabin: other, emission class: none, fuel: biodiesel, Equipment: ABS, compressed air brake, each ramp approx. 2,700 mm long x 560 mm wide, ramps with gratings, loading height: 840 mm, 12 lashing eyes each 2.5 t, 8 x lashing eyes each 6 t, steel drop sides, foldable and removable, wooden planks 50 mm, loading area rear beveled, loading area width inside 2.480 mm, rear stanchion removable, front for through-loading, , Also available in 5,300 mm loading area length!!!, , Rental price from 500 ¤ , , -- Misprints, errors and omissions excepted, sample pictures --, More data under: !, More Details: ! Lsdpfxozr Ui Uj Ahtohk

Condition: used, Year of construction: 2023, load capacity: 7,000 kg, lifting height: 34,700 mm, fork length: 1,200 mm, total length: 10,300 mm, - Lenkart: 2-rad Lenkung, 4-rad Lenkung, Krebsgang - Stützentyp: Dreifach-Teleskop - Steuerung mit Stützen: Stützenbefehle einzeln oder gleichzeitig - Motornorm: Stage V / Stufe 4 - Nennleistung Verbrennungsmotor / Leistung (kW) 211 Hp / 155 kW - Max. Drehmoment / Engine rotation (min) 805 Nm @ 1500 rpm - Anzahl der Zylinder - Tragfähigkeit der Zylinder 4 - 4567 cm³ - Kühlsystem des Motors Wasserkühlung - Anzahl Batterien / Batterie 2 x 12 V - Battery capacity 120 Ah - Battery starting current (EN)850 A - Getriebetyp Hydrostatic with CVT - Getriebe Speedshift - Max. travel speed 40 km/h - Zugkraft 9300 daN - Parkbremse Automatische negative Parkbremse - Festellbremse: Ölbad Lamellenbremsen an den Vorder- und Hinterachsen Ljdpfxozi Hbkj Ahtjhk - Steigfähigkeit - beladen / unbeladen: 29 % / 38.70 % - Pumpenart: Verstellpumpe - Hydraulikfördermenge: 185 l/min - Hydraulikdruck: 350 bar - Motoröl: 13 l - Hydrauliköl: 300 l - Fassungsvermögen des Kraftstofftanks: 320 l - Abgasnachbehandlung für Diesel (AdBlue®): 24 l - Geräuschpegel im Fahrerstand (LpA): 68 dB - Außenschallpegel (LwA): 109 dB - Vibrationswert an Händen/Armen: < 2.50 m/s² - Lenkräder (vorne / hinten): 2 / 2 - Steuerungen: 2 Joysticks - Sicherheit Zulassung der Kabine: Kabine ROPS - FOPS Stufe 2 - Anbaugeräte Erkennungssystem (E-Reco): Standard

Condition: used, Year of construction: 2025, load capacity: 7,000 kg, lifting height: 34,700 mm, total length: 10,060 mm, Lenkart: 2-rad Lenkung, 4-rad Lenkung, Krebsgang - Stützentyp: Dreifach-Teleskop - Steuerung mit Stützen: Stützenbefehle einzeln oder gleichzeitig - Motornorm: Stage V / Stufe 4 Lsdpfx Asztf Scehtshk - Nennleistung Verbrennungsmotor / Leistung (kW) 211 Hp / 155 kW - Max. Drehmoment / Engine rotation (min) 805 Nm @ 1500 rpm - Anzahl der Zylinder - Tragfähigkeit der Zylinder 4 - 4567 cm³ - Kühlsystem des Motors Wasserkühlung - Anzahl Batterien / Batterie 2 x 12 V - Battery capacity 120 Ah - Battery starting current (EN)850 A - Getriebetyp Hydrostatic with CVT - Getriebe Speedshift - Max. travel speed 40 km/h - Zugkraft 9300 daN - Parkbremse Automatische negative Parkbremse - Festellbremse: Ölbad Lamellenbremsen an den Vorder- und Hinterachsen - Steigfähigkeit - beladen / unbeladen: 29 % / 38.70 % - Pumpenart: Verstellpumpe - Hydraulikfördermenge: 185 l/min - Hydraulikdruck: 350 bar - Motoröl: 13 l - Hydrauliköl: 300 l - Fassungsvermögen des Kraftstofftanks: 320 l - Abgasnachbehandlung für Diesel (AdBlue®): 24 l - Geräuschpegel im Fahrerstand (LpA): 68 dB - Außenschallpegel (LwA): 109 dB - Vibrationswert an Händen/Armen: < 2.50 m/s² - Lenkräder (vorne / hinten): 2 / 2 - Steuerungen: 2 Joysticks - Sicherheit Zulassung der Kabine: Kabine ROPS - FOPS Stufe 2 - Anbaugeräte Erkennungssystem (E-Reco): Standard

Condition: used, Year of construction: 2026, load capacity: 6,000 kg, lifting height: 25,800 mm, total length: 9,050 mm, Rotating forklift Magni RTH 6.26 Drive Diesel Year built 2026 Lifting height (mm) 25,800 Ledpsztf S Asfx Ahtjhk Lifting weight (kg) 6,000

Condition: good (used), Hydraulic pump, hydraulic unit, hydraulic container, hydraulic tank Lhodpfjrgtd Ujx Ahtjk -Manufacturer: Safan, hydraulic container from press brake type UC 110-3100 -Level indicator: sight glass -Total dimensions: 1950/540/H485 mm -Weight: 69 kg

Condition: new, empty load weight: 4,580 kg, maximum load weight: 14,420 kg, overall weight: 19,000 kg, axle configuration: 2 axles, loading space length: 5,700 mm, loading space width: 2,420 mm, loading space height: 1,800 mm, loading space volume: 24 m³, suspension: other, tire size: 435/50 R 19,5, color: other, gearing type: other, front tire size: 435/50 R 19,5, rear tire size: 435/50 R 19,5, driver cabin: other, emission class: none, fuel: biodiesel, Equipment: ABS, compressed air brake, Three-sided tipper, loading area approx. 5,700 mm x 2,420 mm, side walls 600 mm + 2 x 600 mm extension side walls, total side wall height approx. 1,800 mm, side walls hot-dip galvanized, loading height approx. 1,080 mm, 12 x lashing eyes in the floor, reinforced gearbox support winch with load and fast gear at the front, 2 x folding supports at the rear, 435/50 R 19.5, chassis and tipper body hot-dip galvanized, surcharge for: aluminum ramps, price: 1,900 euros, -- printing errors, errors and changes excepted, sample images --, more data at: !, More Details: ! Lhsdpfx Aozr Umtohtsk