Castor Types

In general, medical castors can be sub-divided into four main types:

Pressed Steel – typical pressed steel type castors incorporate single and double ball race constructions. The balls run in tracks formed in the fork and top plate pressings.

Die-cast Aluminium – these consist of either a die-cast aluminium body in Twintech twin wheel products or two die-cast aluminium body shells in Singletech single wheel products. Swivel action is by precision ball bearings or cup and cone bearings.

Plastic – consisting of either single or twin wheel castors with plastic bodies. Swivel action is by precision ball bearings or cup and cone bearings.

Highbred – with a mixture of aluminium and/or steel and plastics components.

Medical Castor Terminology

Due to the nature of some of the applications, medical castors may have specially designed fitting methods. In addition to the regular top plate, single bolt hole and threaded stem configurations, a ‘Combi’ stem is often used in applications such as hospital beds where there is a requirement for two or more of the castors to be operated by the actuation of one operating pedal.

The Combi stem consists of a solid stem, or a cam capsule that totally encloses the locking mechanism and is activated by a drive bar, providing one of four modes of operation:

Mode 1: Swivel - wheels and castor free

Mode 2: Total lock- wheel and swivel action locked

Mode 3: Total & Directional lock – wheel and swivel action locked, or wheel free but swivel action locked in the steering position when the brake drive bar is in line with the direction of travel.

Mode 4: Total & Directional lock – wheel and swivel action locked, or wheel free but swivel action locked in the steering position when the brake drive bar is at 90 degrees to the direction of travel.

Wheel Selection

We offer different tyre profiles to suit hard and soft floors along with a choice of materials:

a) Polyurethane, grey or black: hard wearing, low rolling resistance, suitable for temperatures up to 80°C

b) Natural rubber, grey or black, provides a softer ride, for temperatures up to 65°C

c) “Performa” thermoplastic rubber for durability and low rolling resistance

d) Nylon, black: for high manoeuvrability on suitable floors

e) Electrically conductive tyres; available in both polyurethane or rubber

Other tyre colours can be provided, subject to minimum order quantities – please consult factory for further information

Medical Castor Uses

Medical equipment can generally be divided into three broad areas

a) Hospital Beds that can be sub-divided into two main categories: those that have centrally operated braking systems and those that have independent braking systems.

Centrally operated braking systems; where all castors need to be locked simultaneously, Combi castors are the preferred choice. One foot pedal activates the operating function of two or more castors. Options available from Colson include TwinTech Combi, SingleTech Combi and BedMaster Series products. Typical castor layouts are shown as follows:

Independent braking systems; where the castor configuration is made up of a combination of swivel, braked and on occasions a directional lock castor each working independently to each other.

b) Hospital equipment, typical examples of which are all types of imaging equipment, anaesthesia units, laser units, optical equipment, in fact any piece of high-technology requiring mobility. A range of options presents itself when specifying castors for these types of products but where designers need to meet the ergonomic, aesthetic and economic needs of increasingly demanding applications then Solus castors are the preferred choice. Whether you require the soft, streamlined contours of SingleTech Solus that are combined with a design that minimises swivel and pushing effort, or prefer the increased stability and precise tracking offered by TwinTech Solus, they both are available with the widest range of liveries and finishes to add an extra dimension to a customer’s equipment.

c) Patient Hoists – the specially-designed “Lo-Hite” 100mm castors provide maximum wheel size with a minimum build height of 102mm. This provided greater mobility for the operative than conventionally-used 75mm castors.

d) General ancillary equipment: there are numerous pieces of equipment found in medical applications, such as general ward trolleys, drip stands, catering trolleys etc that use castors. We have a broad range of products available for this equipment.

Medical Castor Specifications

TWINTECH Size range

Solus versions: 75/100/125mm

Combi versions: 125/150mm

a) Body and wheel centres; Pressure-die cast aluminium for light weight, high load capacity, resistance to abuse and electrical safety

b) Brake (Solus); Brake mechanism effected through die cast teeth around each wheel hub and swivel pin

c) Brake (Combi); mechanical system with pressure die cast teeth engaging with integral teeth cast into the wheel hub. This is a positively locking parking brake which totally immobilises the equipment. The locking mechanism is totally enclosed within the capsule. It is activated by an 11mm hexagonal drive bar which can be set for three modes of operation

· Swivel - wheel and castor free

· Total & Directional Lock - wheel & castor locked or wheel free but castor locked in the steering position

· Total Lock - wheel and castor locked

d) Tyres; Tyre profiles and materials to suit hard and soft floors

e) Axles; Precision hardened and ground steel shaft, manufactured to exacting tolerances, provides extended service life.

f) Bearings; Headwork thrust race with hardened cup and cone ensures minimum wear and swivel resistance. Precision needle roller bearings fitted in the wheels as standard, for low rolling resistance.

g) Twin wheels; Independent rotation allows minimal swivel effort. Totally enclosed bearings, swivel and brake mechanisms in minimal height housing.

h) Retaining plate (Combi); designed to allow quick removal and reassembly of the wheels for easy cleaning and servicing.

i) Options specification

· Body and wheels can be powder coated in any colour to match existing livery

· Tyres can be polyurethane, rubber or nylon in a choice of colour or electrical characteristic

· Fixing pins (Solus) can be customised to users requirements

· Special ‘Gold Seal’ version provides 72 hour salt spray protection through special plating quality and additional seals for regular autoclaving or steam cleaning

· Overall height of castor can be extended to match conventional single wheel castors, for greater ground clearance and under-trolley access (Combi)

· Alternative ‘D’ section drive bar actuating mechanism can be supplied (Combi)

· Minimum order quantities may apply to some options – consult factory for further information.

TWINTECH ULTRA

The ULTRA version of Twintech has taken the performance of Twintech Combi castors a stage further. Available in 125mm diameter, it offers the following features:

a) Central body; Pressure-die cast aluminium for light weight, high load capacity, resistance to abuse and electrical safety.

b) Brake; Improved, Combi-style braking system, providing a high-performance, maintenance-free dynamic brake that is factory set and does not require any further adjustment. The locking mechanism is totally enclosed within the capsule. It is activated by an 11mm hexagonal drive bar which can be set for three modes of operation

· Swivel - wheel and castor free

· Total & Directional Lock - wheel & castor locked or wheel free but castor locked in the steering position

· Total Lock - wheel and castor locked

c) Wheels; Twin, high-quality thermoplastic, giving weight and cost reductions without compromising performance. Independent rotation allows minimal swivel effort. d) Tyres; moulded-on polyurethane for low rolling resistance and high load capacity.

e) Bearings; Headwork thrust race with hardened cup and cone ensures minimum wear and swivel resistance. Precision ball bearings moulded into wheel centres give low rolling resistance.

f) Combi Cam capsule: the locking mechanism is totally enclosed within the capsule. It is activated by an 11mm hexagonal drive bar which can be set for three modes of operation

· Swivel - wheel and castor free

· Total & Directional Lock - wheel & castor locked or wheel free but castor locked in the steering position

· Total Lock - wheel and castor locked

g) Colour options; Available in white or grey as standard, Twintech Ultra can be colour co-ordinated with your equipment. Minimum order quantities may apply – please consult factory for further information.

SINGLETECH

Size range

Solus versions: 100/125mm

Combi versions: 125/150mm

a) Body and wheel centre; body consists of two pressure die-cast aluminium shells, wheel centres are pressure die-cast zinc alloy or nylon and all are chosen for their light weight, high load capacity, abuse electrical safety and finish characteristics

b) Tyres; available in polyurethane (90° Shore A, up to 80°C), rubber (65° Shore A, up to 65°C), “Performa thermoplastic rubber (80 Shore A up to ? deg C) or nylon to suit floor surfaces, and are moulded and mechanically locked onto the wheel centre

c) Bearings; sealed precision ball bearings are fitted as standard to headwork and wheel, ensuring high dynamic performance and low rolling resistance.

d) Brake (Solus); a progressive brake mechanism grips the flanks of the tyres without affecting the tread of the wheel and therefore reduces tyre wear.

e) Brake (Combi); a progressive brake, the locking mechanism of which is totally enclosed within the capsule. It is activated by an 11mm hexagonal drive bar which can be set for three modes of operation

· Swivel - wheel and castor free

· Total & Directional Lock - wheel & castor locked or wheel free but castor locked in the steering position

· Total Lock - wheel and castor locked

f) Options specifications;

· castor body can be powder coated in any colour to match existing livery

· polyurethane tyres can be moulded in choice of colours, hardness or electrical characteristic (standard colour is grey)

· rubber non-staining tyres can be moulded in choice of hardness or electrical characteristic (standard colour is grey)

· special ‘Gold Seal’ version provides 72 hour salt spray protection through special plating quality and additional seals for regular autoclaving or steam cleaning

· Minimum order quantities may apply to some options, consult factory for further information.

BEDMASTER

Size range

Solus versions: 80/100/125mm

Combi versions: 100/125mm

a) Constuction; Castor manufactured in zinc-plated sheet steel for high strength and cost-effectiveness

b) Brake (Combi); Utilises the maintenance-free,dynamic central-lock braking system designed for the Twintech Ultra. Brake is factory-set and requires no further adjustment.

c) Brake (Solus); Combined wheel and swivel lock, pedal-operated

d) Wheel; High-strength thermoplastic centre with grey, moulded-on thermoplastic rubber tyre.

e) Bearings; Integral twin ball-race swivel bearing and precision ball bearing moulded into wheel as standard, plain bearing versions available.

f) Fixings; 28mm stem (Combi); M12 bolt-hole (Solus)

HOISTMASTER Size range

Solus versions: 100mm

a) Construction; Twin-wheeled castors moulded in Nylon 6 for strength and weight savings.

b) Options:

. Brake; positive, pedal-operated wheel brake

. Free swivel

. Lo-Hite swivel; operating height of castor is only 102mm, even with a wheel diameter of 100mm, meaning that a 100mm castor can be used where normally 75mm castor would be the largest possible.

c) Wheels; Twin wheels in Nylon 6 for strength and supplied with moulded-on polyurethane tyres

d) Bearings; a total of four precision ball bearings are used in each castor, two in the swivel head and one in each wheel, providing tremendous manoeuvrability and strength

e) Fixing; a through-bolt fitting feature means that the castors can be easily and quickly fitted to the application

PLASTECH Size range

Solus versions: 100/125mm

a) Construction; Twin wheels either side of a central Nylon body

b) Options;

- Wheel brake, pedal operated

- Total lock (wheel and swivel action), pedal operated

- Directional lock (125mm castors), pedal operated

- Free swivel

- Stand and Lo-Hite versions available.

c) Bearings; wheels are fitted with precision ball bearings and swivel heads are fitted with needle-roller or plain bearings

d) Tyres; Moulded-on grey polyurethane

e) Colour options; castors are white as standard, although other colours can be supplied, subject to minimum order quantities – please consult factory for further information.

f) Fixings; Threaded stem and plate fittings are offered as standard

TRAVELAID Size range

Solus versions: 115/125mm

Construction; Twin wheels, either side of a central Nylon body

a) Options; - Free Swivel

- Wheel Brake

- Wheel brake with On/Off indicator

b) Tyres; grey or black rubber, black conductive rubber

c) Colour options; Castors are available in grey or black

d) Fixings; threaded stem and plate fittings are available as standard


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