An employee wearing gloves caught his left hand in a roll-forming machine, resulting in partial amputation of two fingers. The employee was standing close to the moving rollers, feeding flat steel sheet from behind and catching it on the front side. There was no point of operation guard on the front roller and the foot operating pedal was very close to the machine.
Roll-forming and roll-bending machines primarily perform metal bending, rolling, or shaping functions. Roll forming is the process of bending a continuous strip of metal to gradually form a predetermined shape using a self-contained machine. Roll-forming machines may also perform other processes on the metal, including piercing holes, or notches; stamping; flanging; and stretchbending. Roll bending is essentially the same process, except that the machine produces a bend across the width of flat or pre-formed metal to achieve a curved or angular configuration. Roll-forming and roll-bending machines frequently are set up and operated by one person.
The most common type of amputation hazard associated with roll-forming and roll-bending machines are point of operation hazards created by in-running nip points. Amputations occur when the hands of the operator feeding material through get caught and are then pulled into the point of operation. Causes of amputations related to roll-forming and roll-bending machines can occur from the following:
§ Having an unguarded or inadequately guarded point of operation;
§ Locating the operator control station too close to the process;
§ Activating the machine inadvertently; and
§ Performing cleaning, clearing, changing, or inspecting tasks while the machine is operating or is not properly locked or tagged out.
Roll-forming and roll-bending machines are available in a wide variety of sizes and designs, and safeguarding methods must be tailored for each machine. Several factors affect the ways to safeguard the equipment, including machine size, operating speed, thickness of product, length of production runs, required production accuracy, sheet feeding methods, and part removal methods. Depending on the size and type of machine, a number of different safeguarding devices and methods may be required to adequately protect the operator as well as other workers nearby. For example, you can do the following:
§ Install fixed or adjustable point of operation guards at the in-feed and out-feed sections of machines. If the stock or end-product does not differ greatly from run to run, a fixed guard may be preferable. If the stock or end-product is variable, however, an adjustable guard may be more suitable.
§ Install fixed point of operation guards to cover the sides of the rollers to prevent an employee from reaching into the in-going nip points of the rollers.
§ Install fixed or interlocked guards to cover any other rotating parts, such as a power- transmission apparatus.
§ Install safety trip controls, such as a pressure-sensitive body bar or safety tripwire cable on the in-feed section of the machine to shut down the machine if an employee gets too close to the point of operation.
§ Install emergency stop controls that are readily accessible to the operator.
§ Use an awareness barrier guard with an interlocking gate around the perimeter of the machine to prevent unauthorized entry.
§ Locate foot pedal controls away from the point of operation and guard them in such a way as to prevent inadvertent activation.
§ Allow only one control station to operate at any one time when a single machine has more than one set of operator controls, this does not apply to the emergency stop controls which must be operable from all locations at all times.
§ Position operating stations in a way that ensures operators are not exposed to the machine’s point of operation.
§ Safeguard operator control stations to prevent inadvertent activation by unauthorized employees.
You can also prevent hazards from this equipment by doing the following:
§ Develop and implement safe operating procedures for roll-forming and roll-bending machines and conduct periodic inspections of the operation to ensure compliance.
§ Ensure that all operators receive appropriate on-the-job training under direct supervision of experienced operators until they can work safely on their own.
§ Ensure that operators use the jog mode during feeding operations if appropriate and that they maintain a safe distance from the machine’s rollers.
§ Require workers to perform servicing and maintenance activities under an energy control program in accordance with §1910.147.
Printing presses vary by type and size, ranging from relatively simple manual presses to the complex large presses used for printing newspapers, magazines, and books. Printing presses are often part of a larger system that also includes cutting, binding, folding, and finishing equipment. Many modern printing presses rely on computer controls, and the high speeds of such equipment often require rapid machine adjustments to avoid waste.
This section discusses amputation hazards associated with two common types of printing presses: web-fed and sheet-fed printing press systems. Web-fed printing presses are fed by large continuous rolls of substrate such as paper, fabric or plastic; sheet-fed printing presses, as their name implies, are fed by large sheets of substrate. In both types, the substrate typically feeds through a series of cylinders containing printing plates and supporting cylinders moving in the opposite direction.
As with other machines, many printing press-related amputations occur during cleaning and maintenance activities. For example, amputations frequently occur when workers get their fingers or hands caught in the in-going nip points created between two rollers while performing these tasks:
§ Cleaning or attempting to free material from the rollers.
§ Hand-feeding substrate into the in-running rollers during press set-up while the machine is operating.
An employee was adding ink at the top of a printing press when he spotted a small piece of wood in the area of the moving rollers. He caught his hand in the moving rollers as he attempted to remove the wood and had to have his forearm surgically amputated.
Source: OSHA IMIS Accident Investigation Database
As with most machinery, you can rely on engineering, work practice, and administrative controls to protect employees against injuries when using printing presses. For example, some basic engineering controls include the following:
§ Install guarding on all hazard points, including all accessible in-going nip points between rollers and power-transmission apparatus (such as chains and sprockets), that are accessible during normal operation.
§ Safeguard nip point hazards with barrier guards or nip guards. Nip guards should be designed and installed without creating additional hazards. For example, the distance between the nip guard and the adjacent roller/cylinder should be minimized. Additionally, to prevent wedging, the angle between the nip guard and the surface the roller should not be less than 60 degrees.
§ Install fixed barrier guards at rollers that do not require operator access.
§ Use fixed guards that can only be opened with tools (to prevent tampering) at points requiring operator access once per shift or less.
§ When you need more frequent access to the press, use interlocked guards, which are designed to stop the printing press when opened or moved, instead of fixed guards. Interlocked guards should not allow normal operation of the press while open.
§ Use an inch or reverse function to perform actions such as substrate feeding, machine adjustment, and lubrication when one or more interlocked guards is moved to allow operator access. The speed and distance of the inch function should be designed to ensure that it does not pose a hazard if not otherwise guarded.
§ Require press operators to perform normal startup procedures before the press can be operated. Replacing an interlocked guard should not automatically trigger machine operation.
§ Use additional safeguarding methods such by location as well as devices for stopping the printing press such as trip bars and pull cords.
§ Remember that interlocks and stops do not stop the press immediately and that non-driven idler rollers may continue to rotate when the press is stopped and can cause injury.
All printing presses should incorporate a signaling system in accordance with ANSI B65.1-1995 as follows:
§ Make sure that printing presses attended by more than one operator or ones outside of the operator’s viewing area be equipped with visual and audible warning devices to alert workers regarding the press’s operational status — in operation, safe mode, or impending operation.
§ Install visual warning devices of sufficient number and brightness and locate them so that they are readily visible to press personnel.
§ Ensure that audible alarms are loud enough to be heard above background noise.
§ Provide a warning system that activates for at least two seconds prior to machine motion.
Work practices and administrative controls recommended for printing presses include the following:
§ Develop and implement safe operating procedures for printing presses and conduct periodic inspections to ensure compliance.
§ Ensure that all press operators receive appropriate training and supervision until they can work safely on their own.
§ Instruct workers to lubricate, align, and maintain printing presses only when presses are stopped. If this is impractical, advise employees to maintain a safe distance from any in-going nip points. Installing extended oiler tubes and adjusting screws will help in these instances.
§ Prohibit employees working with or near printing presses from wearing loose clothing and require them to secure long hair with a net or cap.
§ Perform servicing and maintenance activities under an energy control program in accordance with §1910.147.
In addition, perform minor servicing tasks using the Inch-Safe-Service procedure specified in ANSI B65.1. These include the following tasks: types of paper jams; minor cleaning, lubricating, and adjusting operations; certain platechanging and blanket-changing tasks; and, in some cases, webbing and paper roll changing. The Inch-Safe-Service procedure, at a minimum, calls for the use of a stop/safe drive push-button control. Under this procedure, the stop/safe function cannot serve as the energy control device when you are performing lockout.
Conveyors are used in many industries to transport materials horizontally, vertically, at an angle, or around curves. Types include non-powered and powered, live roller, slat, chain, screw, and pneumatic. Conveyors eliminate or reduce manual material handling tasks, but they present amputation hazards associated with mechanical motion.
Conveyor-related injuries typically involve a worker’s hands or fingers becoming caught in nip points or shear points on conveyors and may occur in these situations:
§ Cleaning and maintaining a conveyor especially when it is still operating.
§ Reaching into an in-going nip point to remove debris or to free jammed material.
§ Allowing a cleaning cloth or an employee’s clothing to get caught in the conveyor and pull the worker’s fingers or hands into the conveyor.
Other conveyor-related hazards include improperly guarded sprocket and chain drives. Overhead conveyors warrant special attention because most of the conveyor’s drive train is exposed. Employees have also been injured while stepping or walking on or near conveyors.
While removing a cleaning rag from the ingoing nip point between the conveyor belt and its tail pulley (non-powered end of the conveyor), an employee’s arm became caught in the pulley, which amputated his arm below the elbow.
Figure 1: Chain driven live roller conveyor
Some general controls you might use for conveyors include the following:
§ Install guards for all sprockets, chains, rollers, belts, and other moving parts. Guarding by location — locating moving parts away from employees to prevent accidental contact with the hazard point — is one option for guarding conveyors. It is particularly difficult, however, to use this method when guarding the in-going nip points on certain conveyors such as roller conveyors because the exposed rollers are crucial to the function of the conveyor.
§ Use prominent warning signs or lights to alert workers to the conveyor operation when it is to install guarding devices because they interfere with the conveyor’s operation.
§ Ensure that all conveyor openings such as wall and floor openings, and chutes and hoppers, have guards when the conveyor is not in use.
§ Ensure that start buttons have guards to prevent accidental operation.
§ Ensure that conveyor controls or power sources can accept a lockout/tagout device to allow safe maintenance practices.
For crossovers, aisles, passageways, you need to do the following:
§ Ensure that all accesses and aisles that cross over or under or are adjacent to the conveyor have adequate clearance and hand rails or other guards.
§ Place crossovers in areas where employees are most likely to use them.
§ Ensure that all underpasses have protected ceilings.
§ Post appropriate hazard warning signs at all crossovers, aisles, and passageways.
§ Considering emergency egress when determining placement of crossovers, aisles, and passageways.
§ Equip conveyors with interlocking devices that shut them down during an electrical or mechanical overload such as product jam or other stoppage. When conveyors are arranged in a series, all should automatically stop whenever one stops.
§ Equip conveyors with emergency stop controls that require manual resetting before resuming conveyor operation.
§ Install clearly marked, unobstructed emergency stop buttons or pull cords within easy reach of workers.
§ Provide continuously accessible conveyor belts with emergency stop cables that extend the entire length of the conveyor belt to allow access to the cable from any point along the belt.
§ Hazards: Conveyor take-up and discharge ends, where the belt or chain enters or exits the in-going nip point; where the belt wraps around pulleys; where the belt changes direction, such as take-ups; or where multiple conveyors are adjoined.
§ Controls: Guarding of belt conveyors is not always feasible because guarding devices interfere with normal operation. Options for hazard control include guarding by distance as well as installing hazard warning signs and signals.
§ Hazards: In-going nip points of turning helical flights for the entire length of the screw conveyor when the housing is opened.
§ Controls: Screw conveyor housing should completely enclose the moving elements of the conveyor except for the loading and discharge points. If such guarding is not feasible, the entire conveyor should be guarded by railing unless it is guarded by location — the hazardous areas cannot be easily accessed by employees. Permanently affixed grids or Plexiglass™ can be installed to allow the operator to inspect the operation. Open troughs can be used if such covers are not feasible; but they should be guarded by location. Alternatively, the trough side walls should be high enough to prevent employees from reaching over falling into the trough.
§ Hazards: Moving chains since the chains can not be enclosed without impairing the function of the conveyor.
§ Controls: Guarding of chain conveyors is not always feasible because guarding devices interfere with normal operation. Options for hazard control include guarding by distance and installing hazard warning signs and signals.
§ Hazards: In-going nip points between the drive chain and sprockets; nip points between belt and carrier rollers; and nip points at terminals, drives, take-ups, idlers, and snub rollers.
§ Controls: Roller conveyors should have permanent guards that can be adjusted as necessary to protect the worker. For example, when transporting small items on a roller conveyor that does not require the use of the entire roller width, the unused section of rollers closest to the workers should be guarded.
§ Develop and implement safe operating procedures for conveyors and conduct periodic inspections to ensure compliance.
§ Allow only trained individuals to operate conveyors and only trained, authorized staff maintenance.
§ Train employees working with or near conveyors regarding the location and use of emergency stopping devices and the proper procedures for conveyor operation.
§ Forbid employees to ride on conveyors.
§ Instruct employees to cross over or under conveyors only at properly designed and safeguarded passageways.
§ Instruct employees to lubricate, align, and maintain conveyors when the conveyor is stopped. If this is impractical, advise workers to perform this work at a safe distance from any ingoing nip points or pinch points. Installing extended oiler tubes and adjusting screws will help in these instances.
§ Prohibit employees working with or near conveyors from wearing loose clothing or jewelry, and require them to secure long hair with nets or caps.
§ Perform servicing and maintenance under an energy control program in accordance with §1910.147.
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