Magnetic braking system and method
A mobile radiography system includes a wheeled transport frame and a vertical column mounted on the transport frame. A boom is attached to the vertical column and to an x-ray tube head. A boom carriage allows movement of the boom along a track in the vertical column and includes a magnetic mechanism to lock the boom in the track at a desired height. An electromagnetic coil in the boom carriage is configured to disable the magnetic lock mechanism to allow vertical movement of the boom along the track.
1. A mobile radiography system comprising:
a transport frame having wheels attached thereto for rollably transporting the system;
a vertical column mounted on the transport frame, the vertical column comprising a vertical track, the vertical track comprising a vertical brake plate;
a boom attached horizontally to the vertical column by a boom carriage configured to travel along the track; and
an x-ray tube head attached to the boom,
wherein the boom carriage comprises:
a brake pad;
a permanent magnet to press the brake pad against the vertical brake plate to prevent vertical movement of the boom carriage along the track; and
an electromagnetic coil to generate a magnetic field to counteract a magnetic field of the permanent magnet and to allow vertical movement of the boom carriage along the track when the electromagnetic coil is activated.
2. The system of claim 1 , wherein the boom carriage comprises a spring to bias the brake pad against the vertical brake plate when the electromagnetic coil is activated.
3. The system of claim 2 , wherein the brake pad is positioned between the permanent magnet and the vertical brake plate.
4. The system of claim 3 , wherein the electromagnetic coil releases the brake pad from pressing against the vertical brake plate when the electromagnetic coil is activated.
5. The system of claim 4 , further comprising a power source electrically connectable to the electromagnetic coil for providing power to activate the electromagnetic coil.
6. The system of claim 5 , further comprising a manually operable switch for electrically connecting the power source to the electromagnetic coil.
7. A brake assembly comprising:
an elongated brake plate;
a brake mechanism configured to freely travel parallel to the brake plate when the brake mechanism is deactivated, the brake mechanism comprising:
a pressure source;
a brake pad configured to be pressed against the brake plate by the pressure source; and
an electrically powered assembly comprising an electromagnetic coil to generate a magnetic field configured to deactivate the brake mechanism when electric power is provided to the electromagnetic coil.
8. The brake assembly of claim 7 , wherein the brake plate is fixed in position relative to the brake mechanism and the brake mechanism is attached to a movable carriage.
9. The brake assembly of claim 8 , wherein the pressure source comprises a permanent magnet.
10. The brake assembly of claim 9 , wherein the permanent magnet is configured to generate a first magnetic field, the electromagnetic coil is configured to generate a second magnetic field, and wherein the second magnetic field negates the first magnetic field when power is provided to the electrically powered assembly.
11. The brake assembly of claim 10 , further comprising a power source and a switch, wherein the switch is configured to electrically connect the power source to the electrically powered assembly to provide power thereto.
12. A radiography system comprising:
a vertical support column having a vertical track and a vertical brake plate therein;
a boom carriage configured to travel vertically along the vertical track;
a horizontal boom attached to the boom carriage; and
an x-ray source attached to the horizontal boom,
wherein the boom carriage comprises:
a brake mechanism comprising:
a brake pad, the brake mechanism configured to press the brake pad against the vertical brake plate to prevent the boom carriage from traveling vertically along the vertical track;
a permanent magnet to press the brake pad against the vertical brake plate; and
an electromagnetic coil to deactivate the brake mechanism, wherein a magnetic field generated by the electromagnetic coil counteracts a magnetic field of the permanent magnet when the brake mechanism is deactivated, and wherein the boom carriage is free to travel vertically along the vertical track when the brake mechanism is deactivated.
13. The system of claim 12 , further comprising a power source to power the electromagnetic coil to generate the counteracting magnetic field.
14. The system of claim 13 , further comprising a manual switch for connecting the power source to the electromagnetic coil to deactivate the brake mechanism.
15. The system of claim 14 , wherein the manual switch is configured to disconnect the power source from the electromagnetic coil when the manual switch is manually released.