Laser transmitter having gimbal support and method of preventing the gimbal support from contacting the transmitter housing

• US 7,932,484 B2
• Filed: 03/03/2008
• Issued: 04/26/2011
• Est. Priority Date: 03/03/2008
• Status: Active Grant

• Current Assignee: Spectra Precision Inc. (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Hajmousa, Ayman
• Primary Examiner(s): Ko; Tony
• Application Number:
  US12/041,147
• Publication Number:
  US 20090231596A1
• Time in Patent Office: 1,149 Days
• Field of Search: 250/234, 250/216, 356/615, 356/614, 356/138
• US Class Current: 250/216
• CPC Class Codes: G01C 15/00 Surveying instruments or accessories not provided for in groups G01C1/00 - G01C13/00

Abstract

A laser transmitter has a transmitter housing and a laser source in the housing. A gimbal support arrangement supports the laser source in the housing and includes a gimbal motor arrangement for moving the gimbal support arrangement and said laser source in said housing. A gimbal motor drive circuit actuates the gimbal motor arrangement to cause the gimbal support arrangement to move in said housing. A plurality of optical proximity sensors sense the orientation of said gimbal support arrangement to the interior of said housing. By this arrangement, damage to the transmitter is prevented.

Claims

1. A laser transmitter, comprising:

a transmitter housing;

a generally flat, circuit board stator;

a rotor defining a central opening;

a bearing, supporting said rotor for rotation about a rotation axis that is generally perpendicular to said generally flat, circuit board stator, and that is aligned with the center of said central opening;

a laser source, mounted on said stator, for providing a beam of laser light directed outward from said circuit board stator in alignment with said rotation axis;

a pentaprism assembly mounted on said rotor for rotation therewith, said pentaprism assembly receiving said beam of laser light through said central opening and redirecting at least a portion of said laser light outward in a direction normal to said rotation axis;

a gimbal support for supporting said stator within said transmitter housing;

a gimbal motor arrangement for orienting said gimbal support; and

a plurality of pairs of light sources and light sensors for sensing the proximity of said circuit board stator with respect to the interior of said transmitter housing.

2. The laser transmitter of claim 1, in further comprising a plurality of reflectors on the interior of said transmitter housing for reflecting light from said light sources to corresponding light sensors in said pairs.

3. The laser transmitter of claim 2, in which said reflectors are adjustably positioned with respect to said housing.

4. A laser transmitter comprising:

a transmitter housing;

a laser source in said housing;

a gimbal support arrangement for supporting said laser source in said housing, and including a gimbal motor arrangement for moving said gimbal support arrangement and said laser source in said housing;

gimbal motor drive circuit for actuating said gimbal motor arrangement to cause said gimbal support arrangement to move in said housing; and

a plurality of optical proximity sensors, movable with said gimbal support arrangement, for sensing the orientation of said gimbal support arrangement with respect to the interior of said housing, whereby damage to said laser transmitter from movement within said transmitter housing is prevented.

5. The laser transmitter of claim 4, in further comprising a plurality of reflectors inside said transmitter housing for reflecting light from said optical proximity sensors.

6. The laser transmitter of claim 5, in which said reflectors are adjustably positioned with respect to said housing.

7. The laser transmitter of claim 5, in which there are four optical proximity sensors for sensing the proximity of the sensors to the interior of said housing, said four proximity sensors being spaced uniformly around the periphery of said gimbal support arrangement.

8. The laser transmitter of claim 7, in which the outputs of said four optical proximity sensors are combined to determine the amount of tilt of said gimbal support arrangement in the direction of maximum tilt.

9. A laser transmitter, comprising:

a transmitter housing;

a laser source and support structure;

a gimbal support for supporting said laser source and support structure within the transmitter housing; and

a plurality of optical sensors on said support structure for sensing the proximity of said support structure to the interior of said transmitter housing.

10. A laser transmitter according to claim 9, in which said optical sensors each comprise a light source and a light sensor, said sensor providing an indication of the amount of light reflected from the interior of said housing.

11. A laser transmitter according to claim 9, in which said transmitter includes a control circuit responsive to said plurality of optical sensors, for determining the amount of maximum tilt experienced by said support structure based upon the outputs from multiple sensors.

12. A laser transmitter according to claim 9, including four optical sensors equally spaced around the circumference of said support structure.

13. A laser transmitter according to claim 9, in which said transmitter includes reflectors inside said transmitter housing cooperating with said optical sensors.

14. A laser transmitter according to claim 9, in which the maximum tilt of the support structure is determined by reference to a look up table.

15. A method of positioning a laser source and support structure in the housing of a laser transmitter, said transmitter including a gimbal support for supporting said laser source and support structure, comprising the steps of:

providing a plurality of optical sensors on said support structure;

sensing the proximity of the interior of said transmitter housing with each of said optical sensors; and

preventing said support structure from being moved into contact with the interior of said transmitter housing.

16. The method of positioning a laser source and a support structure in the housing of a laser transmitter, according to claim 15, further comprising the step of determining the maximum tilt of said support structure based on outputs from said optical sensors.

17. The method of positioning a laser source and a support structure in the housing of a laser transmitter, according to claim 16, further comprising the step of limiting the maximum tilt to a predetermined maximum such that said support structure is prevented from contacting said interior of said housing.

18. The method of positioning a laser source and a support structure in the housing of a laser transmitter, according to claim 15, in which the step of providing a plurality of optical sensors on said support structure includes the step of positioning said optical sensors around the periphery of said support structure.

19. The method of positioning a laser source and a support structure in the housing of a laser transmitter, according to claim 18, in which the step of positioning said optical sensors around the periphery of said support structure includes the step of spacing four optical sensors equally around the periphery of said support structure.

20. The method of positioning a laser source and a support structure in the housing of a laser transmitter, according to claim 19, further comprising the step of determining the maximum tilt of said support structure based on outputs from said four optical sensors, such that the maximum tilt can be determined regardless of the axis along which it occurs.