Solution Summary: Hand Jackhammer
A hand jackhammer is an engineering control that reduces the risk of musculoskeletal disorders (MSDs) associated with stressful upper extremity activities and stooped postures. The tool consists of a tubular steel body and a solid steel tool bit. While standing in an upright posture, the operator first lifts the handle and then drops or forcefully slides it down over the tool bit to deliver an impact blow to the top end of the tool. Many interchangeable tool bits are available to permit digging, cutting, driving, chipping, and compacting.
A hand jackhammer is an engineering control that reduces the risk of musculoskeletal disorders (MSDs) associated with stressful upper extremity activities and stooped postures. Hand jackhammers are useful for digging, cutting, driving, chipping, and compacting. They can be utilized for many different materials and settings.
The Callander Hand Jackhammer has a tubular design with a simple handle (Figure 1.). When fully extended, the hand jackhammer is 72 inches long. The handle is 34 inches, weighs 13 lbs, and has a “stoke” of 24 inches. The interchangeable tool bits are approximately 39 inches and weigh between 12 – 15 lbs.
Figure 1. The Callander Hand Jackhammer
There are five different interchangeable tool bits available for the Callender Hand Jackhammer. The diamond point is used for breaking up hard ground and concrete, and digging holes (Figure 2).
Figure 2. The Diamond Point
The narrow chisel is used for breaking up concrete, bricks, and stone, as well as splitting timber (Figure 3).
Figure 3. The Narrow Chisel
The wide chisel is used for breaking up concrete, and cutting asphalt or tree roots.
Figure 4. The Wide Chisel
The tamper is used for compacting soil or other soft ground.
Figure 5. The Tamper
The tyre bead breaker is used for breaking the bead on all types of tires.
Figure 6. The Tyre Bead Breaker
The RAM Rod Impact Tool utilizes a heavy-duty spring, added weight, and a large handle (Figure 7.). It has an operational trigger for mechanical release and trigger lock for continuous use. A "vertical handle" is helpful for operation on a wall or other vertical surface.
Figure 7. The RAM Rod Impact Tool
The RAM Rod has five diferrent interchangeable tool bits available. These include: 1" Spike bit, 6.5" Scraper bit, 3", 2", and 1" Chisel bits (Figure 8.)
Stressful hand and wrist activity and hand-arm vibration can cause musculoskeletal disorders (MSDs) such as muscle strains; tendonitis, which is inflammation of elbow and wrist tendons; or carpal tunnel syndrome, which is compression of a wrist nerve, resulting in finger numbness and loss of hand strength. A hand jackhammer reduces stressful upper extremity activities because it requires less energy expenditure to operate compared to a spud bar (digging bar, crowbar) due to its lighter weight . Also, when performing chipping, cutting, and demolition activities, the hand jackhammer has less vibration that could lead to wrist and hand injury when compared to using a standard jackhammer.
Stooped postures can cause low back disorders, such as muscle strain or a disc herniation (“slipped disc”), which is bulging of disc material possibly pressing on the spinal cord or nerves that go into the leg. A hand jackhammer can reduce stooped postures because it can be operated while standing upright.
How Risks are Reduced:
The hand jackhammer allows workers to perform chipping, cutting and demolition activities with less force on the arms and shoulders due to its lighter weight, and it has less vibration than a traditional jackhammer. The hand jackhammer also allows for the worker to stand upright avoiding stooped postures.
The manufacturer believes that a hand jackhammer can reduce the amount of stressful upper extremity activity because the hand jackhammer requires less effort to generate force through the tool bits. The manufacturer states, “On average the tool delivers around twice the force at the point of impact.” Also, the tool requires, “nearly 25% less energy expenditure to operate compared to the crowbar which is an advantage from a ‘manual handling’ viewpoint.”
Safety and health experts agree that a hand jackhammer can reduce the amount of upper extremity activity necessary to performing chipping tasks, which may reduce the risk for developing upper extremity MSDs. In addition, a hand jackhammer minimizes stooped postures because it can be operated while standing straight.
Effects on Productivity:
A hand jackhammer can increase productivity on the worksite
The hand jackhammer is not designed to be used as a lever.
Dan Anton, PT, PhD, ATC; Kevin Wright, SPT; and Neil Morris, SPT - Eastern Washington University