MN FACE Investigation 95MN00601
DATE: July 17, 1995
Hired Farm Worker Dies After Being Crushed By A Stalk Chopper
A 34-year-old male hired farm worker (victim) died from injuries sustained when a stalk chopper he was working on fell. The chopper was hooked to a farm tractor and parked in a farm yard. A removable hydraulic cylinder had been improperly installed in the chopper and was used to raise the front of the chopper. The victim crawled underneath the raised chopper to lubricate several bearings. A concrete block had been placed on the ground below each end of the chopper frame but not in contact with it. The chopper was not equipped with a mechanical transport link to securely lock it in a raised position. While the victim was underneath the chopper, a damaged hydraulic cylinder hose ruptured and the chopper fell on him. The farm owner discovered the victim shortly after the incident occurred. He got onto the tractor, started the engine and raised the chopper by activating the hydraulic system. The farmer's wife pulled the victim from beneath the raised chopper and cardiopulmonary resuscitation was administered. Emergency medical personnel were called to the scene and transported the victim to a local hospital. He was airlifted to a major medical center where he died several hours after the incident. MN FACE investigators concluded that, in order to reduce the likelihood of similar occurrences, the following guidelines should be followed:
On March 25, 1995, MN FACE investigators were notified of a farm work-related fatality which occurred on March 22, 1995. The county sheriff's department was contacted and releasable information obtained. This information included a copy of their reports of the incident and copies of their photos of the incident site. A site investigation was not conducted by MN FACE investigators.
The victim was working alone performing general service and maintenance on a stalk chopper at the time of the incident. The chopper was hooked to a farm tractor and parked in a farm yard. Photographs of the chopper showed a removable hydraulic cylinder improperly installed in the chopper lifting mechanism as depicted in Figure 1 (a). When it was installed, it was turned 180 degrees or end for end. The improper installation of the cylinder resulted in the hoses being closer to the power takeoff shaft than if the cylinder had been properly installed.
While the tractor and chopper were parked in the farm yard, the hydraulic cylinder held the front of the chopper at or near it's highest possible position. Sometime prior to the incident and while the chopper was raised, the tractor's power takeoff apparently was engaged to operate the moveable components of the chopper. Photographs of the cylinder hoses indicated that the end of the power takeoff shaft nearest the chopper contacted and damaged one of the hoses while the power takeoff shaft rotated. After the chopper components rotated for a period of time, the tractor's power takeoff was disengaged and the chopper was stopped.
The victim crawled underneath the raised chopper to lubricate the bearings on which the chopper shaft rotated. An 8 inch x 8 inch x 16 inch concrete block had been placed on the ground in a horizontal position below, but not in contact with each end of the chopper frame. While the victim was underneath the chopper, the damaged cylinder hose ruptured and the chopper fell on him. The photographs showed the chopper sitting on the concrete blocks approximately 8 inches above the ground. The farm owner discovered the victim shortly after the incident occurred. He got onto the tractor, started the engine, and raised the chopper by activating the hydraulic system. The farmer's wife pulled the victim from beneath the raised chopper and cardiopulmonary resuscitation was administered. Emergency medical personnel were called and transported the victim to a local hospital. He was airlifted to a major medical center where he died several hours after the incident.
CAUSE OF DEATH
Since a copy of the death certificate has not been received, the exact cause of death is unknown at this time.
Recommendation #1: All raised equipment should be adequately blocked if workers are required to crawl underneath the raised unit.
Discussion: If it is necessary for workers to crawl under any raised equipment unit or other item, the item should first be adequately blocked. The unit should be blocked with wood or other material which will not crush under the weight of the unit. The blocks should be high enough to contact the frame of the unit and minimize the distance the unit can fall. Although concrete blocks were placed under the ends of the chopper frame, they were not large enough to prevent the chopper from falling on the victim. If the chopper involved in this incident had been adequately blocked prior to the victim crawling under it, this fatality might have been prevented.
Recommendation #2: Removable hydraulic cylinders should be properly installed.
Discussion: Removable hydraulic cylinders are used in many types of farm equipment and consist of a cylinder case and a movable ram or shaft. The cylinder hoses are connected to one end of the cylinder case and enable hydraulic fluid to enter and exit the cylinder. These cylinders are easily and quickly connected to and disconnected from equipment lifting mechanisms by two large coupling pins. One pin is located at the base of the cylinder case, and the other is located at the exposed end of the cylinder ram or shaft. Lifting mechanisms on farm machines have a fixed anchor point and a pivot point. When properly installed as in Figure 1 (b), the base of the cylinder case is coupled to the fixed anchor point and the exposed end of the cylinder shaft is connected to the pivot point. When the hydraulic system is activated, the cylinder case remains fixed with respect to the machine or equipment and the cylinder shaft moves back and forth as the machine is raised and lowered. Since the coupling pins are usually the same diameter, a cylinder can be rotated end for end and improperly coupled to the lifting mechanism as in this incident. If the cylinder involved in this incident had been properly installed, this fatality might have been prevented.
[Note: Removable hydraulic cylinders will function whether properly or improperly installed in the lifting mechanism of farm machines. However, improper installation of a cylinder will create a dangerous situation if, with the cylinder shaft fully retracted, the cylinder hoses are just long enough to reach from the tractor to the equipment lifting mechanism. When the hydraulic system is activated, the cylinder hoses may be torn or the hose couplings broken if the cylinder case moves away from the tractor versus toward the tractor. This could result in a worker being injured by a machine which suddenly falls or by a spray of high pressure fluid which is suddenly released.]
Recommendation #3: Transport links, if present, should be coupled together before working underneath raised equipment.
Discussion: Many types of farm machines that use removable hydraulic cylinders are equipped with a transport link. A transport link is usually a steel bar that is connected at one end to a fixed point on the frame of a machine. The other end may be connected, via a removable pin to the lifting mechanism of a machine when the machine is in its raised position. The removable cylinder can then be retracted and removed from the machine and the machine remains in a raised position for transport on roadways.
Although the chopper involved in this incident was not equipped with a transport link, it is recommended that they be used whenever machines are equipped with them. Transport links, when used, provide an additional measure of protection against a machine falling on workers who may be required to crawl underneath them.
Recommendation #4: Farm equipment manufacturers should produce removable hydraulic cylinders and equipment lift mechanisms that reduce the likelihood of improper installation.
Discussion: The two coupling pins on removable hydraulic cylinders used on many types of farm machines are standardized with respect to length and diameter. In addition, the cylinder coupling holes on farm equipment lifting mechanisms are the same diameter as the cylinder pins. As a result, removable hydraulic cylinders can be easily installed either correctly or incorrectly. If automatic locking pins of different diameter were used on the ends of cylinders and if the diameter of equipment lift coupling holes correspond to these diameters, cylinders could not be improperly installed unless these safety measures were circumvented. By designing cylinders such that the likelihood of improper installation were reduced, potentially hazardous situations that might result in injury or death to workers could be reduced or eliminated.
1. Agriculture Safety, Fundamentals of Machine Operation, 1987, Deere & Company, Moline, Illinois, Third Edition.
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