PRINCIPLE OF OPERATION

Traditional alignment systems have a rigid mounting post for clamping the bottom bracket shell. The operator uses long "cheater bars" to apply force to adjust the frame. The problem is that once the frame gives, the force must be reduced, or the frame will be over bent. Even with practice, it is hard to guess how much force to apply to straighten the frame without over straightening it, or possibly buckling it.

To provide better control of the process, the Henry James system holds, in any sequence, the head tube, the seat tube and each rear dropout at a height of 95 mm. (3.740") above the beam. The bottom bracket shell shaft is pivoted. If the part of the frame being checked is aligned, the shaft will be perpendicular to the beam. If the shaft is not perpendicular, the frame needs to be straightened by applying force to the pivoted shaft.

Because the movement occurs at the shell, the motions involved are small enough that dial gauges can measure the amount of error. The dial gauges also indicate how far the frame is being deflected during realignment. To apply the straightening force in a controlled and efficient way, the patented Henry James system uses a ball nut and screw operated with a crank. Our key advantage is that a predetermined amount of deflection is applied under total control, rather than using the traditional approach of trying to control an impossible to quantify load. With the Henry James Alignment System, when the frame gives, it bends only as far as it can bend for the increment of deflection applied. By applying small deflections increments, over-straightening and buckling are avoided when using the Henry James Alignment System.

Other alignment systems try to control the loads applied to determine the straightening. The inherent and unavoidable problem with this is that when a metal begins to yield, the over stressed extremities are no longer able to carry any of the load. This means that the cross section of the metal that is capable of carrying load is now smaller. The load being applied is not affected by this, so the stresses in the metal increase, and more yielding occurs, UNLESS THE LOAD IS IMMEDIATELY REDUCED! The frame will be destroyed if the load is not reduced in time. This is why the experienced technician must "bounce" on the cheater bar, instead of applying steady force. This is not a very high tech way of doing things. Back problems are an undesirable side effect of this lunging activity.

Another unique feature of the Henry James Alignment System is that the bending loads are all reacted internally to the system. This feature, combined with the low input efforts the ball screw and crank require, means that the system can be mounted almost anywhere. We offer a simple Vise Mount for shops with limited room. A Floor Mount is also available, which can be bolted to the floor or a base plate. Another practical approach is to simply hold the Floor Mount in a WorkMate(tm) portable work bench. Because the bending loads are reacted internal to the system, this simple approach works fine.