This invention relates generally to pliers, and more particularly to locking pliers.
The wires that run through an aircraft and engine compartment need to be secured into bundles to prevent interfering with moving parts or chafing. Adel Clamps, also known as MS21919 aircraft clamps, are key components used in line support, vibration dampening, and maintaining proper clearance for lines or wire harnesses running throughout the aircraft structure. An Adel Clamp is a metal band made from aluminum, corrosion-resistant steel, and low-carbon steel, covered by a rubber lining or cushion made from silicone.
A visual inspection, no matter how trivial, needs to include an inspection of these clamps to determine whether they need to be replaced. The lining or cushions of the clamps are exposed to heat, vibration, ozone, and a variety of petroleum-based and synthetic-based fluids. Over the years, inspections have found cushions torn or missing, thereby exposing the metal bands. These clamps should be replaced.
When a careful examination of an Adel clamp reveals that the cushion has worn away on the inside of the band, possibly creating a bare-band-to-line or -wire condition, the clamp should be replaced.
When an Adel clamp fails in these ways, it has been observed in fuel systems to cause non-designed fuel migration, or a low fuel pressure situation. In hydraulic lines, Adel clamp bands have been found rubbing through hydraulic system lines, resulting in a loss of hydraulic quantity. Intermittent electrical faults have led technicians to find an Adel clamp cutting into an electrical harness.
The MS21919 aircraft clamp has been used safely by many aircraft OEMs with very little trouble. However, a skilled technician must look closely at these clamps to verify that they are in good condition, and further knows that their replacement is not easy, but is necessary. The cost to repair the many systems they support vastly outweighs the cost of replacing the clamps as simple preventive maintenance.
The bifurcated locking pliers of the invention are very useful for working with wire harnesses in the aircraft industry. The bifurcated locking pliers are particularly good for easy installation, inspection, and removal of Adel clamps that are used to secure wire harnesses, hydraulic lines, fuel lines, pneumatic lines, and other aerospace/aviation related systems. To use the bifurcated locking pliers, simply position an Adel clamp and compress it using the bifurcated locking pliers. Then, affix the hardware using a fastener. Next, remove the bifurcated locking pliers, and tighten the fastener until secure.
A general aspect of the invention is a locking pliers for enhanced control of Adel clamps during installation, inspection, and removal of such clamps. The locking pliers includes: a first plier arm having a first bifurcated grasping portion, a first pivot portion, a first handle portion extending from the first pivot portion, the first handle portion ending in a series of ridges; and a second plier arm having a second bifurcated grasping portion, a second pivot portion pivotably connected to the first pivot portion, a second handle portion extending from the second pivot portion, the second handle portion ending in a wedge, the wedge being cooperative with the series of ridges so as to serve as an adjustable locking mechanism.
In some embodiments, the handle portions are coated with cushioning grip material.
In some embodiments, the cushioning grip material is made from rubber or silicone.
In some embodiments, the first and second bifurcated grasping surfaces have smoothed edges.
In some embodiments, the locking pliers further includes a leaf spring configured to resiliently resist bringing the first handle portion and the second handle portion together.
In some embodiments, the first plier arm and the second plier arm are made from high-carbon steel.
In some embodiments, the first plier arm and the second plier arm are of equal length, the length being within a range of: 8″ to 12″.
In some embodiments, the first bifurcated grasping portion and the second bifurcated grasping portion exhibit mirror symmetry.
In some embodiments, each bifurcated grasping portion includes a slot having a width configured to accommodate a screw.
In some embodiments, the first handle portion has an arcuate shape, and the second handle portion has an arcuate shape.
Another aspect of the invention is a locking pliers for enhanced control of Adel clamps during installation, inspection, and removal of such clamps. These locking pliers include: a first plier arm having a first bifurcated grasping portion having a slot of a width configured to accommodate a screw, a first pivot portion, a first handle portion extending from the first pivot portion, the first handle portion ending in a series of ridges, the first handle portion coated with cushioning grip material; a second plier arm having a second bifurcated grasping portion having a slot of a width configured to accommodate a screw, a second pivot portion pivotably connected to the first pivot portion, a second handle portion extending from the second pivot portion, the second handle portion ending in a wedge, the wedge being cooperative with the series of ridges so as to serve as an adjustable locking mechanism, the second handle portion coated with cushioning grip material; and a leaf spring configured to resiliently resist bringing the first handle portion and the second handle portion together.
In some embodiments, the cushioning grip material is made from rubber or silicone.
In some embodiments, the first and second bifurcated grasping surfaces have smoothed edges.
In some embodiments, the first plier arm and the second plier arm are made from high-carbon steel.
In some embodiments, the first plier arm and the second plier arm are of equal length, the length being within a range of: 8″ to 12″.
In some embodiments, the first bifurcated grasping portion and the second bifurcated grasping portion exhibit mirror symmetry.
In some embodiments, the first handle portion has an arcuate shape, and the second handle portion has an arcuate shape.
Many additional features and advantages will become apparent to those skilled in the art upon reading the following description, when considered in conjunction with the accompanying drawings, wherein:
With reference to
Also, a second plier arm 112 includes a second bifurcated grasping portion 114, a second pivot portion 116, and a second handle portion 118 having a wedge 120 for engaging with the series of ridges 110, the wedge 120 being located at the end of the second plier arm 112. The wedge 120 works cooperatively with the series of ridges 110 as an adjustable locking mechanism.
As the pliers 100 are closed, the bifurcated grasping surfaces 104 and 114 move towards each other, while the wedge 120 engages with one pair of ridges of the series of ridges (two or more ridges) 110 at the end of the first handle 108, thereby keeping the bifurcated grasping surfaces 104 and 114 from separating. If there are three ridges, there are two possible locations for the wedge 120 to engage. If there are four ridges, there are three possible locations for the wedge 120 to engage, each location representing a different degree of compression. The first pair of ridges facilitates a first amount of compression of the first bifurcated grasping portion 104 towards the second bifurcated grasping portion 114. If the user further presses the first handle portion 108 towards the second handle portion 118, the wedge 120 will move beyond the first and second ridges to settle between the second and third ridges, thereby locking the pliers 100 closed with greater compression of the first bifurcated grasping portion 104 towards the second bifurcated grasping portion 114.
Thus, it is possible to select an amount of compression applied by the pliers 100 by simply moving the wedge 120 along the ridges 110 until a desired amount of compression is achieved.
To release the compression, the user simply pushes the wedge 120 perpendicularly away from (rather than along) the ridges 110 so as to disengage the wedge 120 from the ridges 110, thereby allowing the bifurcated grasping portions 104 and 114 to move apart.
With reference to
Note that the first handle portion 108 and the second handle portion 118 are coated with cushioning grip material 206 and 208, respectively. The cushioning grip material 206 and 208 can be either rubber or silicone, or any material that adds cushioning to the handle portions 108 and 118.
Referring to
With reference to
Referring to
With reference to
Referring to
Referring to
Referring to
Referring to
Referring to
Referring to
Other modifications and implementations will occur to those skilled in the art without departing from the spirit and the scope of the invention as claimed. Accordingly, the above description is not intended to limit the invention, except as indicated in the following claims.