Glossary of Industry Terms

Seizing is the worst-case of galling. Anti-seize refers to ways of preventing galling and seizing. In the case of lockrods, Powerbrace uses nylon bushings between the lockrod and mounting brackets. In the case of Glide-Pro™ hinges, impact-modified nylon bearings are used.

A bearing is a nylon hinge barrel insert that eliminates friction, especially between the rotating pin and the hinge barrel. 

A brushing is a nylon sleeve used behind guide plates and rod guides.

Also known as: “locking dog”, “knuckle,” and “end”. This is the component welded on each end of a lockrod. The purpose of a cam is to reach and gather while engaging the keeper during door closure, and to resist racking and end-wall forces while the door is closed.

Cams at the top and bottom of the lockrod need to work together to properly engage with the keepers and properly hold doors closed. To do this, the cams should be “in time” While there are a few exceptions, this normally means the flat backside of the top and bottom cam are in-line with one another.

Corrosion is the degradation of a material. Most corrosion results from galvanic corrosion, which occurs when two metals of different types (dissimilar metals) are in contact with each other and in contact with an electrolyte, such as water or even moist air.

• One way to prevent corrosion is to physically isolate the different metals. For example, the use of Powerbrace’s Glide-Pro™ bearings separates the aluminum hinge from the steel pin and separates the aluminum hinge from the steel butt.
• Another way to prevent galvanic corrosion is through the use of a sacrificial coating on the parts, such as galvanizing, which sacrifices itself and corrodes, preserving the base metal it is protecting.

Electropolish is a process which removes a minimal amount of base material to produce a highly reflective surface. In the case of stainless steel, electropolishing creates a highly passivated surface, maximizing corrosion resistance of the base stainless steel. Powerbrace offers electropolished stainless steel lockrods and mounting brackets, and aluminum hinges that are virtually chrome-shiny, without the maintenance of chrome.

Galling is a severe form of contact wear that shows up as torn areas (gouges) on a metal surface. Galling can occur on hinge pins and the I.D. of hinge barrels, or on lockrod tubing and lockrod mounting brackets if nylon bushings are not used. In a worst-case scenario, seizure can occur. Stainless steels are particularly susceptible to galling, and it is for this reason that using a SS hinge pin directly in a SS hinge is not recommended. To combat galling, Powerbrace lockrods include nylon bushings between the lockrod tubing and mounting brackets and Powerbrace Glide-Pro™ hinges include impact-modified nylon bearings.

A corrosion-resistant zinc coating applied over steel. Powerbrace applies hot-dip galvanizing (HDG) to our steel components, including lockrods. This provides the longest-lasting corrosion protection possible. We follow ASTM A123 and ASTM 153, which, depending upon the component, specifies a thickness of 2.2 mils to 3.9 mils. As a rule-of-thumb, galvanizing thickness of 0.1 mil provides one-year of service life (22-39 years of protections on Powerbrace parts). Note: That standard G90 steel sold by steel warehouses only has a 0.75 mil thickness (7.5 years of protection). For additional information about galvanizing, read our technical bulletin on the subject.

The ability of a lockrod model to align the door when the rear frame is out-of-square. Rear frames become out-of-square if the trailer is parked with one side up on a curb, if the trailer is loaded unevenly, or if the trailer is old and loosened with age.

A trailer that is designed to maximize interior area. Often, high cube trailers have a narrow header and other attributes that reduce end-frame strength. As a result, some high cube trailers experience more racking than standard trailers, placing additional stresses on the lockrods, hinges and hinge butts.

Tubing which had a yield strength higher than standard. Yield strength indicates the stress required to permanently deform the material. Standard supply-house tubing may have a 30,000psi or 35,000psi minimum yield strength, but most* Powerbrace lockrods are made using a minimum 55,000psi yield strength tubing. Additionally, Powerbrace tubing is manufactured with demanding diameter and straightness tolerances that far exceed standard supply-house tubing. The specification for stainless steel lockrods is 30,000 min. yield.

A lockrod model with high door opening leverage. Called an icebreaker because of its ability to open doors that are frozen shut.

Also known as “lock socket.” This is the component welded or bolted to the end-frame whose purpose is to provide secure engagement for the cam.

The header is the portion of a doorframe above the doors. The upper door seal seals against the header, and lockrod keepers are fastened to the header. On high cube trailers, the header is often small in its vertical dimension, leaving minimal space for mounting the top keepers. Powerbrace has cam/keeper models specifically designed for narrow headers—NH, SH, and others.

The distance from the plane of the door to the plane of the door frame (end-frame). If they are flush, the offset is 0”. If the door is ¼” beyond the plane of the end-frame, there is a ¼” offset. If 3/8” beyond the offset is 3/8,” etc. Depending upon the model, keepers and hinge butts may be available in the offset you require.

The swaying motion of a trailer going down the road, (or a trailer on a railcar, or a container on a railcar). This destructive motion fatigues frame joints and body rivets on the trailer, wears hinges and doors seals, and can cause structural fatigue throughout the trailer. The bottom container of a double stack on a railcar is particularly susceptible to racking stress. While all the Powerbrace’s door hardware is designed to resist racking forces, there are several products designed with racking resistance as a main goal. These models include DL and NH.

The ability of a lockrod cam to “reach” and engage the keeper while closing the door. This feature helps to overcome resistance from compression seals and warped doors.

Refers to cams that mount to the lockrod tubing by straddling the outside of the tubing, much like a saddle. The cam is welded to the tubing, usually with two straight-line welds. Saddle mounted cams are generally easier to fixture when making your own lockrods or when installing the top cam on a TEL lockrod.

A condition where components become restricted from proper movement and interaction. Seizing is caused when metals rub against each other and wear stresses are created. Seizing is an extreme form of galling.

Refers to cams that are mounted to the lockrod tubing by inserting the cam’s shank into the tubing . The cam is welded to the tubing over the full diameter where the end of the tubing meets the cam.

Some Powerbrace models have keepers which can be used for a left-hand lockrod or a right-hand lockrod. In these cases, the keeper is symmetrical. A benefit of using symmetrical keepers is inventory reduction. Instead of stocking three or four different keepers, two may suffice. Take a step further, if the same model is used top and bottom, this inventory can be brought down to one keeper (an example is the Powerbrace NH-NH model, where the same keeper is used top, bottom, left and right).

Indicates a lockrod manufactured without a pre-welded top cam. Keeping a small inventory of TEL lockrods allows a trailer builder to assemble special length lockrods as needed. For use, the lockrod tubing is cut to the desired length and the top cam is welded in place at the desired cam position. When assembling TEL lockrods, take care to make sure cam timing is precise and to coat the freshly welded area with an anti-corrosive coating.

Wet storage stain is a white or gray stain that can occur on newly hot dip galvanized parts when subjected to moisture such as rain or even high humidity. Generally, wet storage stain is cosmetic only, disappears with weathering, and does not affect the excellent long-term corrosion resistance of galvanizing. To minimize wet storage stain, Powerbrace takes steps such as bundling finished lockrods so they do not touch one another during transport to your plant and uses a special corrosion inhibiting paper for packing of some galvanized components.

A lockrod that is designed with a cam that engages the keeper in such a way as to go “over center” when closed (similar to a locking pliers or toggle clamp). What this means is that the higher the load against the door, the tighter the cams engage the keepers. This is desirable for applications such as livestock trailers.