TECHNICAL DESCRIPTIONPARTNER1998-12

PARTNER K950/K1250 ACTIVEThe Partner K950 Active and K1250 Active are a newgeneration of cutters in the big-machine class. Theyare characterised by low weight in relation to poweroutput, allied to ergonomics of exceptional class.

The Partner K950 Active has a power output thatplaces it among the largest machines on the market,but it weighs no more than a medium-class machine.It is available in variants for three blade sizes: 12˝, 14˝and 16˝.

The Partner K1250 Active has the highest poweroutput among all cutting machines on the market. Itsweight/power ratio is also unbeatable. It is availablewith 14˝ and 16˝ blade sizes.

The Active generation was launched with theK650/K700 medium-class machines. The ideas andequipment concepts developed there have been re-fined and transferred to the K950 and K1250 Active.

Both machines share the same basic design, andseveral of their characteristics place these machinesin a class all their own:

– Highest power in relation to weight.

– Ergonomic design to ensure that the machine iscomfortable and simple to use, and at the same timesafe in everyday operation.

– Operating reliability, long service life and minimum

service requirements, all of which are crucial to goodcutting economy.

– The unique Active Air Filtration system effectivelycleans the intake air utilising three different filtrationprinciples, thus promoting long service intervals.

– The SmartCarb™ carburettor maintains a constantblend of air and fuel irrespective of the condition ofthe air filters. As a result, the machine’s performanceis virtually unaffected by dirty filters. Unchangedpower output between services and lower emissionsare two of the benefits of the new carburettor.

– The starter. The Dura Starter is totally sealed fromdust and features grease lubrication. The pulley isspring-loaded and is thus not subject to vibration-induced wear. (Applies only to the K950 Active.)

– New cutting blade shield which is automaticallyadjusted to suit the machine’s movement.

– Encapsulated cutting arm protects the transmis-sion from dust and water. This design eliminates beltslip when wet-cutting.

– Partner offers a range of accessories and top-classcutting blades with properties honed specifically forfree-hand cutting.

1. Centrifugal force is the first stage in cleaning theintake air of the K950/K1250 Active. Centrifugal cleaningwas previously only used on larger engines in dustyenvironments, for example for construction machines(cyclone air filter).

The fan vanes onthe flywheel supply thecylinder with cool air atthe same time as they actas the active part of thecentrifugal filtering sys-tem for the engine’s in-take air. An intake nozzleis fitted just beside thefan vanes. Under centri-fugal force, the largerparticles do not followthe curved current of airto the nozzle but are in-stead thrown against the outside of the nozzle. Only verysmall dust particles will be able to follow the current ofair leading into the intake. Tests show that up to 80% ofall dust is removed by the centrifugal cleaning process.

2. The foam filteris the next stage ofseparation in the filtra-tion process. This filtercovers the housing’sentire surface, thusoffering a filter surfaceof no less than 3.5 dm2

(K950), 3.7 dm2 (K1250). The filter’s base distributes airacross the entire filter surface, so the filter performs uniformly.

The filter is immersed in oiland is made up of three layers,each intended for a differentpore size.

Inside the filter, the air flowsthrough a structure pretty muchlike a labyrinth. Dust particleswhich strike against the filtersides do not bounce off butinstead fasten to the sticky oilysurface. A dry foam filter offersfar less efficient cleaning perfor-mance than an oil-soaked filter.

An oiled foam filter is by farthe most effective filter for clea-ning of stone dust, since theentire filter volume is used as a“dust trap”, not just the surface. The total dust-absor-bing filter area is accordingly enormous. The foam filterabsorbs about 95% of the total dust volume remainingafter centrifugal filtering. It can be washed clean andmust be oiled at each service.

3. The paper filter deals with thesmall amount of dust particles which,more by chance than anything else,may manage to slip through the foamfilter. Only a tiny amount of extremelysmall dust particles will ever get asfar as the paper filter. The filter’sdense network of cellulose fibrestraps all incoming particles. The paper filter also servesas a protective barrier during filter services. The paperfilter should be changed at every service.

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Filter SystemCutting in stone and concrete generates tiny dust parti-cles which must at all costs be prevented from enteringthe engine. The design of the air filter and its maintenan-ce are the two most important factors governing the ser-vice life of the cutter. Designing a good air filter systemis a matter of balancing effective filtering with long ser-vice intervals.

The development of more efficient filters has improvedair-cleaning performance, but service intervals have bytradition still been inconveniently short in cutting machi-nes. Machine rental firms inherit the problems caused bycustomers who do not carry out the necessary serviceduring the rental period, or are faced with the cost of tra-velling frequently to various work-sites to carry out thenecessary service.

Dust consists of extremely fine particles, generally sosmall that the individual particle cannot easily be disting-uished by the naked eye but which in larger quantitiescan be seen as a cloud of dust. The stone or concretedust which generally results from cutting operationsgenerates the most damaging kind of particles for anengine’s sliding or rotating components. Together withoil, this dust forms a perfect grinding paste which quick-ly wears down pistons, piston rings, cylinder walls andengine bearings once it penetrates an engine.

We generally measure dust particles in µm (1 µm =0.001 mm), thousandths of a millimetre, and the particlesizes which are dealt with by the filter system generallymeasure between 50 µm and 5 µm. (It takes roughly 2minutes for a stone particle measuring 10 µm to fall 1 min wind-still conditions.)

One physical characteristic which is vital to the func-tion of the Partner Active Air Filtration system is thebehaviour of dust particles in air currents depending onparticle size:

A small particle is more easily affected by a current ofair than a larger particle.

The reason for this is that small particles have a largersurface in relation to their mass. A small particle can the-refore be steered and guided more easily by a current ofair while a larger particle succumbs to centrifugal forceor the force of gravity.

Partner Active Air Filtration is a filter system whicheffectively cleans the air entering the engine in threeseparate stages, utilising three different cleaning princi-ples. The most immediate practical benefit of Active AirFiltration is that the service intervals are far longer com-pared to previous systems.

In

To carburettor

Cylindercooling air

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Air filtration principle

CarburettorSmartCarb™– carburettorwith integra-ted filter compensationWith theSmartCarb™carburettor, themachinealways oper-ates with thecorrect air/fuelmixture, virtu-ally irrespective of how soiled the filters are. This design results in:- high and more uniform engine power- better filter economy, longer service intervals- lower fuel consumption- lower emissions

Carburettor oper-ating principleTo understand theway in which theSmartCarb™ car-burettor operates,we will first de-scribe how a con-ventional carburet-tor works.

The carburettor’s main job is to supply the right mix-ture of fuel and air to the engine. Every carburettor has aVenturi tube (A), in which the high speed jet (B) for petrolsupply is fitted. When the engine sucks in air through thecarburettor, the fuel is sucked down into the Venturi tubeand mixed with the air.

A more detailed explanation is that when the air flowsthrough the Venturi tube, air velocity increases, thus caus-ing pressure to drop in the Venturi (the Bernoulli theorem).The pressure differential between the carburettor’s fuelchamber (P1) which operates under constant air pressure(atmospheric pressure), and the Venturi tube’s negativepressure (P2), causes the fuel to flow out through the jet.

Dirty filtersOne problem withthe conventionalcarburettor is thatthe air/fuel ratiogradually changesas the filters be-come increasinglyblocked with dirt.

Dirty filters in-crease air resistance and promote a drop at (P3) which isadded to the pressure drop in the venturi (P2), so thatthe pressure differential compared with the carburettor’sfuel chamber (P1) increases. As a result, the carburettorenriches the mixture, supplying more fuel in relation toair, which in turn impairs the engine’s performance.

One way of compensating for dirty filters is naturally to reduce the amount of fuel being supplied by adjustingthe high-speed needle in the carburettor.

SmartCarb™The SmartCarb™ filter-compensating carburettor has anair duct (C) which links the carburettor’s fuel chamberwith the intake, which is directly connected to the filterchamber. (Note the fuel chamber’s sealed lid and thefixed high-speed nozzle.)

The air duct (C)ensures that the airpressure in the fuelchamber (P1) andthe filter chamber(P3) remains con-stant at all times.Only the pressuredrop created bythe venturi tube(P2) determines the amount of fuel which is to be mixedwith the intake air. Therefore, irrespective of whether thefilter system is clean or dirty, the relationship between airand fuel will remain constant at all times.

The above diagram (showing a laboratory test) demon-strates the considerable effect of SmartCarb™ on enginepower. Air pressure is measured at the carburettor’s inletand the figure 0 is set for brand-new filters and with theengine running at normal speed. As the filters accumu-late dirt, the pressure drops owing to the increasedbuild-up of air resistance.

At a pressure drop of just 100 mm Vp, the standardcarburettor provides such a rich fuel/air mixture that thefilters must be replaced or the H-needle has to beadjusted. The SmartCarb™ carburettor offers excellentengine performance all the way to 500 mmVp.

With the standard carburettor, the engine loses powermainly because it is having to work with the wrongair/fuel ratio, while the power drop with the SmartCarb™– which only becomes apparent once the filters areseverely polluted – stems from the fact that the enginereceives less air and fuel owing to the air resistance caused by the blocked filters.

Long service intervalsIn practical terms, the pressure drop in the diagram canbe translated into corresponding operation times, wherewe can see that the SmartCarb™ engine offers manytimes the standard operating duration between filter service!

H-needleP1

P3 P2

C

P1

P3 P2

60

80

100

0 100 200 300 400 500Pressure drop over filter (mm water)

Power %

Intake air

H-needle

A B

P1

P2

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Vibration and heat-insulated carburettorEvery engine gives off a certain degree of vibration. Thecarburettor has a number of moving parts such as thecontrol valve with its lever and diaphragm and the car-burettor’s throttle spindles. Their function is affected byvibration, with the effect growing in proportion to themass (weight) of the parts. (Light parts have a greaterability to follow vibration-induced oscillation than doheavy parts.)

The carburettor and its moving parts are larger in largemachines, so the K950and K1250 Active feature a vibration-damping element between the cylinderand carburettor.

This element alsoserves as a heat in-sulator and preventsthe formation ofvapour in the carbu-rettor.

Decompression valveLarge engine offersrelatively high resis-tance at the startercord. The decom-pression valve solves this problemin a simple and effi-cient way.

When starting the machine, the valve is first openedby pressing the button. When the operator pulls the star-ter cord, most of the compression pressure exits throughthe valve and the starter cord’smovement is both gentle andeven. As soon as combustiontakes place in the cylinder, thevalve is shut automatically bythe combustion pressure andthe engine operates normally.

Cylinder/piston

The Partner K950 Active and K1250 Active have special-ly developed air-cooled two-stroke engines running onunleaded 95-octane petrol. They are lubricated with oilmixed in the petrol.

There are twotypes of flushingduct - open andclosed. Large two-stroke engines workmore efficiently withclosed flushingducts, which is whythe K950 andK1250 Active feature this system.

The cylinder bore is hard-chromed. The piston has twopiston rings, and it has needle bearings at the couplingwith the connecting rod.

The cylinder and piston are made in a way whichensures ideal dimensions during operation. The piston isprofile-turned and the cylinder is honed for the tempera-ture — and the accompanying material thermal expan-sion — which each part of the cylinder and piston expe-rience during operation. For example, the piston, whenseen from the side, has a somewhat barrel-shaped profi-le, while the view from above reveals a slightly asymme-trical oval shape.

This design gives the engine maximum power throughperfect sealing in the cylinder chamber allied to mini-mum frictional loss against the cylinder wall. However,this production method is both complex and expensive.

Starter unitThe Dura Starter is a new patent-pending starter unitdesigned specifically for the dusty operating conditionsin which cutting machines are used. The Partner K950Active is the largest machine to feature Dura Starter.

Dura Starter — new dust-excluding designThe principle of the new starter unit is that the pulley isprotected from vibration-induced movement. This makesit possible to fit a series of seals and a grease-lubricatedbearing.

The spring above the pulley exerts a tensioning forceagainst the centre screw and acts as a brake on vibra-tion-induced movement. An O-ring above the spring pre-vents dust from penetrating into the pulley’s bearing. Thespacer sleeve around the centre screw is the pulley’supper bearing point and the entire pulley is journalled ina slider bearing against the starter casing’s bearing pin.

The space between the pulley and the spring cassetteis shaped like a circular labyrinth, which prevents dustfrom moving towards the centre. The spring cassette issealed against thecentre with a spring-loaded sealing liplying against thepulley.

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Return spring

Sealing lip

Spring

O-ring

Starter cord

Spring cassette

Pulley

Starter casing

Journal bearing

K950 Active K1250 Active

Open Closed

Ignition systemThe ignition sys-tem is complete-ly sealed and hasno moving parts.It is insensitive tomoisture anddirt. It is desig-ned so that theignition pointnever needs tobe adjusted.

The Partner K950 and K1250 Active feature a built-inover-revving protector in the electronic module, limitingengine speed to 9,750 rpm.

The ignitionsystem con-sists of the pri-mary coil (A)and the secon-dary coil (B),both of whichsurround theiron core (C).A transistorisedelectronic mod-ule (D) dealswith the contact-breaking function.

Current is generated in the primary coil when the fly-wheel’s permanent magnet passes the coil and producesthe voltage sequence shown in the diagram below. (The dotted line shows the voltage which is generated ifthe current is not broken.)

The ignition point is determined by the electronicmodule which senses variations in voltage in the primarycoil and cuts the current at the right level, at the sametime as the piston is just below top dead centre. At theinstant that the contact is broken, voltage in the primarycoil rises from 5 V (volts) to about 200 V through a pro-cess of induction.

In the secondary coil, a high tension of about 20,000volts is conveyed to the spark plug.

SilencerThe silencer is of the single-chamber type and theexhaust gases are directedtowards the side – awayfrom the operator. Thepanel between the cylinderand carburettor cools theexhaust port.

Most of the sound fromthe machine comes from theescaping exhaust gases.

The air filter system acts as an effective intake damperand goes a long way to reducing sound pressure sincethe intake air is not drawn from above the engine. Soundlevels are measured according to the CE norm in two ways:– Sound pressure, measured at the operator’s ear.– Sound level, the mean value of the acoustic powerwhich the machine generates, measured at twelve pointsaround the machine on a reflective flooring material(concrete). These measurements are taken at idlingspeed and maximum speed. See the technical specifications on page 11.

ClutchThe clutch located betweenthe engine and the cutter isof the centrifugal type. Atidling speed, the clutchshoes are held against thecentre by a spring. Thismeans that the cutter discis at a standstill when themachine runs at idlingspeed. As the engine in-creases speed, the springcan no longer hold the shoes in place, and the shoes arepushed against the clutch drum by centrifugal force.Engagement speed is about 3400 rpm. At normal oper-ating speed, centrifugal force is so high that a suddenoverload on the cutter disc will cause the belt to slipagainst the pulley.

Self-lubricating clutch bearingThe clutch bearing on the K950 and K1250 Active islubricated automatically – a tried and tested Partner speciality. A duct in the crankshaft opens out at theclutch bearing. The over-pressure which is created in the crankcase is transferred to the clutch bearing andkeeps the bearing clear of incoming dust particles and at the same time lubricates it.

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Electroniccircuitbreaker

STOPcontrol

Volts+

-

0

Ignitionpoint

SNS

N1

1

A DBC

2

2

3

3

A

B

CD

Ignition system principle

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Machine bodyThe machine body is cast in magnesium alloy for highstrength and low weight. The block is conventionallysplit into two crankcase halves.

The Partner K950 and K1250 Active feature an innova-tive machine-body construction. The machines feature aseparate vibration-damped unit encompassing the fueltank, rear handle and machine base plate, to the front ofwhich the handle arch is attached. As a result, the massof the handle system is greater, which in turn reducesvibration levels. Separation of the fuel tank from the engine body keeps the fuel cool, eliminating disruptionscaused by vapour formation in the fuel system.

Ergonomic designThe K950 and K1250 Active are noted for the clean, slimlines of their engine bodies and the absence of protru-ding parts — all so the operator can work as comforta-bly and safely as possible.

In normal cut-ting operations,the machine ismoved straightback and forthin the cuttinggroove, and theoperator isclose to themachine — insome jobs evenmaintainingdirect bodily contact with the machine. Protruding partson the machine body may easily force it off its intendedcutting line if the machine comes into contact with theoperator or an adjacent object. This is naturally a sourceof irritation and may even constitute a safety hazard.

So Partner cutters owe their clean lines to functionalrequirements — with the added bonus of an attractiveappearance.

Slim machine bodyBoth the K950 Active and the K1250 Active feature amachine body with minimum width, placing the centre ofgravity near the operator. This property is of utmostimportance to operating comfort and when carrying themachine.

Surface treatmentThe machine body is powder-painted, which means thatno solvents are used. Powder paint is sprayed onto themachine body, which is electrostatically charged, to pro-duce a uniform coating which penetrates everywhere.The parts are then baked in an oven and the powderpaint melts to form a thick surface layer which is durableand resistant to mechanical wear.

Crankcase bearingThe crankcase has sturdily dimensioned ball-bearings.These are lubricated by the two-stroke oil mixed in thefuel. The crankshaft’s sealing rings can be replaced fromoutside the machine.

Crankshaft/connecting rodThe crankshaft andconnecting rod areforged and case-har-dened to ensure topstrength and durabili-ty. The connecting rodhas needle bearingson the crankshaft.

Fuel tankThe fuel tank is integrated with the vibration-dampedhandle unit, thus minimising heat transfer from thecrankcase.

Tank volume is sufficient for about 25 – 30 minutes of operation.

Fuel filterThe pick-up, which also has a fuelfilter, always remains at the bottomof the tank so the cutting machineis always assured of its supply offuel irrespective of the angle ofoperation.

The filter design is new. It ismade of sintered polyethyleneplastic which filters out the smal-lest particles. Its high filtration efficiency reduces wearon the carburettor’s moving parts. The filter surface issmooth and repels dirt. The filter-replacement intervalhas thus been increased several times over.

RefuellingThe Partner designers have chosen to position the fuelfiller in line with the machine body so as to avoid protru-sions which may get in the way during cutting opera-tions. The tank cover hangs securely from the machineduring refuelling.

In order toavoid spillagefor environmen-tal and safetyreasons whilerefuelling, werecommend thetype of fuel-canwhich featuresan overfill valve.

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Handle systemErgonomics have top priority in the design of everyPartner cutter. In practical terms, this means the machine must be comfortable and safe to use. A well-built tool will not tire or burden its operator. More workgets done and the risk of injuries is minimised, both inthe long and the short term.

The distance between the handles is important foroverall ergonomics. A short gap means the operatormust use greater force to advance and hold the machineon course. If the distance is too great, the machine isdifficult to control.

The ideal distance, as onthe K950/K1250Active, corres-ponds closely tothe shoulderwidth of theuser.

Handle grips in line with thecutter bladeA design in which the line of gripon the front and rear handles isaligned with the cutter blade,gives the best conditions for safeand efficient cutting. The cutterblade is automatically pressedstraight down into the cuttinggroove, and the cut is straight.Crooked cutting grooves wastepower and impose extra wear onthe cutter’s frame and segment.

Horizontal cutting is more difficult compared to themore common vertical cutting. In vertical cutting, mostof the machine’s weight is exerted on the object beingcut and the feed pressure is applied on the front handle.

In horizontal cutting, however, the operator has tosupport the machine. The front handle’s forward-positio-ned grip in the horizontal position shifts the weight to therear handle, thus creating better balance. The operatorcan easily and comfortably provide feed pressure withhis body against the air filter housing, with the supportof the handle arch.

Vibration suppressionIn prolonged use, vibrating handles cause injuries to theblood vessels in the hands (TVD, often termed “whitefingers”). In brief use, vibration results in impaired sensi-tivity and muscle strength in the hands which, apart fromthe discomfort, also heightens the risk of accidents.

Suppressing vibration in the handle system is some-thing of a designer’s balancing act. A firm handle systemwould, in theory, provide perfect contact and control ofthe machine, if we disregard the harmful effects of vibra-tion. Maximum vibration suppression, on the other hand,would permit considerable movement between handleand machine which would result in poor control over themachine during cutting. A good handle system is alwaysa matter of combining optimum vibration suppressionwith good control over the machine.

New design The K950/K1250 Active differ from other Partner cuttersin that the handle unit is integrated with the fuel tank andbase plate, at the front of which there is a vibration-suppression element. With this design, weight has beentransferred to the handle system. The greater mass inthe handle unit considerably cuts vibration levels, parti-cularly in the case of high-frequency vibration.

The four damper elements consistof steel springs with a rubberdamper pad at the handle arch.The dampers are placed as farfrom each other as possible, thusachieving a good compromisebetween vibration suppressionand operating convenience.

Safe starting positionThe rear handleon Partner cuttersis designed toaccommodate alarge boot, idealfor locking themachine in a safestarting position.

ControlsThe basic principle behind the controls needed while themachine is running is that the operator should not needto release his grip on the handle. Therefore, all the con-trols are gathered together on the rear handle – for bothsafe and comfortable operation.

The size and the shape of the controls make themeasy to operate with thick gloves on – gloves shouldalways be used for cutting operations.

Throttle controlThe throttle control hasbeen thoroughly tested. The spring-loaded counter-balance, its stroke, designand precise positioning areall optimised for best “finger-tip comfort”.

Throttle trigger lockoutThe throttle control is block-ed in the idling position – asafety device to preventaccidental acceleration. Theinhibitor, on the upper faceof the handle, is releasedwhen the driver grasps thehandle.

Starting throttle catchThe throttle control can belocked in a partially opensetting which ensures thecorrect throttle opening forstarting, with either a coldor warm engine. As soon asthe throttle control is pres-sed, the catch is released.

ChokeOn the K950/K1250 Active,the choke control is pulledoutwards, a more easilynoticeable indication thatthe choke is engaged. Thechoke control does not acton the throttle shutter;instead, the partial-throttlesetting is governed by the starting throttle catch during start-up.

Stop controlThe stop control can beoperated with the thumbwithout the operator havingto release the handle. Thecontrol cuts the ignition.

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Cutting unitBelt driveThe cutter blade on the K950/K1250 Active, as on mostother Partner cutters, features one drive belt leadingfrom a pulley on the crankshaft to the pulley on thespindle shaft. This design has the multiple advantages ofsimplicity, reliability and low weight.

It is also important from the safety viewpoint. If thecutter blade comes to a sudden stop, the drive belt willslip and allow the engine to come to a halt more slowly.The cutter arm is split to permit convenient belt replace-ment and adjustment of belt tension.

Fully sealed transmission casingLarge machines like the K950 and K1250 Active areoften used for wet-cutting operations. Water on the beltfunctions as a lubricant but also increases the risk ofbelt slip. These machines are therefore equipped with a

sealed casing that preventswater from reaching the belt.Dust is also kept away from thebelt, thus reducing wear. In orderfor the transmission to be suffici-ently cooled, the casing featurescooling-air vents at the clutch.

Semi-automatic belt tensioningOpinions as to what is the “correct” belt tension varyfrom one operator to another. Partner’s semi-automaticbelt tensioning system solves this problem – a standard-ised spring provides the correct tensioning force.

In precisely controlled experiments in the laboratory,Partner has computed the optimum belt tension whichgives the belt maximum service life allied to perfectapplication pressure before it slips against the pulley.

Belt tensionhas to be ad-justed occasion-ally owing tostretching andwear of the belt.This is donequickly in threestages.

Drive beltThe drive belt in a cutting machine is subjected to se-vere and uneven loads and sometimes also to immenseload peaks. The drive belt also operates on relativelysmall-diameter pulleys, which imposes particulardemands on the belt. To the naked eye, original-specifi-cation Partner belts may look like any other drive belt,but they are specially designed for their specific func-tion. The belt-tensioning rating, which is determined bythe adjustment spring, is tested using genuine Partnerbelts.

Blade guardThe blade guard is by far the machine’s most importantsafety feature. The normal task of the blade guard is todirect cutting dust away from the operator, but it mustalso stand up to the effects of a malfunctioning blade.The blade guard is made of steel plate, with its thicknessdoubled at the periphery.

Self-adjusting blade guardThe blade guard is of anew design. Instead offixed settings, it features a friction lock which auto-matically adjusts the posi-tion of the guard to suit

current operatingsettings.

Generally, the rear edge ofthe blade guard should reston the object being cut. Theeffect of this is that the par-ticles follow the path createdby the guard and are ejectedahead at relatively lowspeed.

Wet cuttingWet cutting vir-tually eliminatescutting dustand the blade iscooled at thesame time,which in turnprolongs theblade’s servicelife.

The bladeguard is facto-ry-prepared forattachment toPartner’s wetcutting kit.

The wet cut-ter adapter hasbeen redesigned and is quickly fitted in place. The nozz-les are fitted on simply to the blade guard with a screwon the outside securing them in place. The control onthe handle arch is used to regulate the volume of waterdelivered to the cutter blade. The supply hose is nowequipped with a standard Gardena® quick-release coupling.

Simple blade replacementThe blade guard has agenerous cut-out to aidblade replacement. Thisopening also gives the operator a clear view of the working surface during cutting.

Rotation-inhibited flangewashersBoth the inner and the outerflange washers are locked inplace against the spindle shaftso they cannot rotate. The dualconnecting flange locks theblade in place securely, even ifthe lock-screw is only tighte-ned moderately. This designalso prevents undesirable self-tightening. As usual, thelock-screw is right-threaded and features a permanentwasher.

Replaceable blade bushingPartner cutting machines can be equipped with centrebushings to suit various standards. Replaceable centrebushings are available for diameters of 20.0 mm, 22.2mm, 25.4 mm (1”) and 30.5 mm. The Partner K950/K1250 Active are supplied as standard with differentcentre bushings to suit the market on which they are sold.

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Reversible cutter armThe cutter arm can bereversed. This makes itpossible to cut close to awall or at floor height withthe blade guard as the onlylimiting factor, in otherwords about 20 mm fromthe cutter blade. Naturally,some of the machine’sergonomic benefits are lostwhen the cutter arm isreversed, but the ability tocarry out certain operationsmay in fact depend on thisfeature.

Peripheral speedPeripheral speed is measured inmetres per second and is directlyproportional to engine speed. Bydefinition, peripheral speed is thespeed at which a given point onthe blade’s circumference travelsthrough the air. It is also thespeed which a given diamondsegment, for instance, has in relation to its point of con-tact during cutting. Another way of looking at the term“peripheral speed” is to imagine a cutting machine as amoving vehicle with the cutter blade as the driven wheel.A speed of 5,100 rpm with a 300 mm cutter blade wouldgive the following speed:

Blade circumference: 0.3 m × π = 0.94 mBlade speed: 5,100 rpm = 85 r/sCircumference × speed = peripheral speedPeripheral speed = 0.94 m × 85 r/s = 80 m/sComputed into a “vehicle-type situation” this gives aspeed of about 290 km/h!

Partner cutter blades are made for peripheral speedsof 100 m/s. A European colour code prescribes a greencolour for a maximum peripheral speed of 100 m/s,while a red colour indicates max. 80 m/s.

BLADE TYPESHand-heldpower cutters requirecutting bladeswhich areapproved foruse in hand-held machines– it is not per-missible to fitthem with bla-des intendedfor fixed-posi-tion bench-mounted machines, for example. The speed markingmust match or be higher than the figure on the machine’sspecification plate. Partner cutting blades are naturallyintended for Hand-held cutting.

– The diamond blade is becoming increasingly commonfor cutting concrete, stone, asphalt and similar materials.The general advantage of the diamond-tipped blade isthat it retains its cutting depth virtually throughout its lifeso cutting efficiency remains high. Used correctly, itoffers excellent blade economy.

Partner “PowerCut” diamond blades are available forprofessional and occasional users. The range encom-passes several grades which are selected to suit thetype of material to be cut. Diamond blades are availablefor both dry and wet cutting.

– Abrasive discs, which used to be the norm for cuttingall materials, are now used primarily for cutting metals.Partner abrasive blades are available for steel and conc-rete, the concrete blade is also very suitable for cuttingsofter steel types such as reinforcing rods and structuralsteel.

– Partner Rescue is a special blade with a TCT hard-metal cutter. It may only be used by specially trainedpersonnel in emergency rescue situations.

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Cutter bladesSpecification plateAll Partner power cuttersare equipped with a plateon the blade guard whichdetails all the importantspecifications needed forchoosing cutter blades.

The dimensions whichthe operator needs toknow are the following:

Blade diameterBlade diameter is given in eithermm or inches.

Three models are available inthe Partner K950 Active range,with cutting blade sizes 300 mm(12˝), 350 mm (14˝) and 400 mm(16˝). Two Partner K1250 Activemodels are available, with 350mm (14˝) and 400 mm (16˝) cuttingblades respectively.

Centre diameterThe cutter blade’s fitting holesmust exactly match the bushingdiameter on the spindle shaft.Various standards are availabledepending on the countries inwhich the machines are sold.The most common standards are20.0, 22.2, 25.4 (1˝ ) and 30.5 mm.Bushings for Partner Power Cuttersare available for these diameters and can be replaced.

SpeedAll cutter blades are marked with a speed which is usuallymeasured in revs per minute(rpm) and which indicates therotating speed which should notbe exceeded. The blade’s maxi-mum speed is determined by theblade manufacturer.

The Power Cutters plate also indicates a speed whichis determined by the machine manufacturer and which istermed the “nominal speed”.

The nominal speed is the speed which is stated on themachine plate and which determines which marking theblade must have in order to be used with the machine.The cutter blade should be marked with the same or higher speed than that specified on the machine plate.

The maximum speed of the machine is a rating whichdoes not affect the machine operator, so it is not speci-fied on the machine but it is used, for instance, as acontrol parameter at the service workshops. The maxi-mum speed is the highest permitted speed which thespindle shaft is allowed to achieve with an unloadedblade and the engine running at full throttle.

According to the European norm, the maximum speedmay not exceed the nominal speed specified on themachine by more than 10%. For example, a machinewith the nominal speed of 5,100 rpm should neverexceed a max. speed of 5,100 × 1.1 = 5,610 rpm.

rpm

m/s

11

EngineK950 ActiveAir-cooled, 2-stroke 94 cm3

Power 4.5 kWBore/stroke 56 mm/38 mmCompression ratio 10.0:1K1250 ActiveAir-cooled, 2-stroke 119 cm3

Power 5.8 kWBore/stroke 60 mm/42 mmCompression ratio 10.0:1

FuelPetrol, min. 90 octane unleaded (green pump)Oil mixture 4% (1:25)Oil mixture with Partner-oil 2% (1:50)Tank volume K950 Active 1.0 l

K1250 Active 1.25 lFull tank under normal operation lasts approx. 25–30 min.

CarburettorK950 ActiveTillotson HS282A SmartCarb™ with built in filter com-pensation.K1250 ActiveWalbro WG 9 SmartCarb™ with built in filter compen-sation.

Air filterThree filtration principles:1. Active centrifugal filtration2. Oil-immersed 3-layer foam filter

Filter area K950 Active 3.5 dm2

K1250 Active 3.7 dm2

3. Dry filter, folded paper filter 16 dm2

Ignition systemTransistorised ignition system, Electrolux typeSpark plug NGK, BPMR7A or Champion, RCJ7YElectrode gap 0.5 mm

ClutchCentrifugal clutch with 3 clutch shoes.Engagement speed, min. 3,200 rpmAutomatic lubrication of clutch bearing.

Blade guardMade of steel. Self-adjusting.

Blade bushingReplaceable centre bushing for hole diameters:20.0 mm, 22.2 mm, 25.4 mm (1˝) and 30.5 mm.

TransmissionBelt type V-belt

Sound levelK950 ActivePressure 102.6 dB(A)Power 111.7 dB(A)K1250 ActivePressure 102.0 dB(A)Power 114.6 dB(A)

Vibration levelsK950 ActiveIdling, front/rear handles 8/9 m/s2

Full throttle, front/rear handles 6/8 m/s2

K1250 ActiveIdling, front/rear handles 7/7 m/s2

Full throttle, front/rear handles 5/6 m/s2

The CE marking indicates that the manufacturer guarantees that the machinemeets all the requirements of the EU direc-tives, that is to say those safety standardswhich must be met in order for the machineto be sold within the EES block.

K950/12˝ K950/14˝ K950/16˝ K1250/14˝ K1250/16˝

Cutting blade, diam. 300 mm (12˝) 350 mm (14˝) 400 mm (16˝) 350 mm (14˝) 400 mm (16˝)Cutting depth 100 mm (4˝) 125 mm (5˝) 145 mm (6˝) 120 mm (5˝) 145 mm (6˝)Nominal speed, blade spindle 5,400 rpm 5,400 rpm 4,700 rpm 5,400 rpm 4,700 rpmTransmission ratio, engine/spindle 1/0.52 1/0.52 1/0.42 1/0.51 1/0.47

Dimension with blade:Length 765 mm 790 mm 815 mm 865 mm 890 mmMax. width 220 mm 220 mm 220 mm 240 mm 240 mmMax. height 365 mm 425 mm 465 mm 440 mm 480 mm

Weight, without blade 9.9 kg 10.3 kg 11.2 kg 13.4 kg 14.3 kg

Packaging:Dimensions carton, mm 700×240×460 700×240×460 715×240×510 780×260×510 780×260×510Quantity per pallet 15 units 15 units 15 units 12 units 12 units

Technical specifications PARTNER K950/K1250 Active

Partner Industrial ProductsSE-433 81 PARTILLE, Sweden

Tel: +46 31 94 90 00. Telefax: +46 31 94 91 14 AR

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