Apparatus for counterbalancing a rotating arm in an imaging system

Patent metadata

Field	Value
Publication number	US-9510798-B2
Application number	US-201414502333-A
Country	US
Kind code	B2
Filing date	Sep 30, 2014
Priority date	Sep 30, 2014
Publication date	Dec 6, 2016
Grant date	Dec 6, 2016

Abstract

An apparatus for balancing a statically unbalanced system, particularly useful in balancing X-ray and mammography systems having an X-ray source and detector mounted to a rotational arm, includes a spring mechanism which synchronizes the activation of the spring mechanism with the rotation of the arm of the mammography system. The balancing system reduces the amount of torque necessary to rotate the arm and decreases the overall inertia of the system by eliminating the need for counterweights to maintain balance of the system.

First claim

What is claimed is:

1. An imaging apparatus, comprising:
a base support;
an arm rotatably coupled to a rotating component, the rotating component coupled to the base support at a pivot point to provide rotation of the arm about an axis of rotation;
an imaging component coupled to an end of the arm and defining a body having a mass “m”; and
a balancing system to balance a torque of the arm, the balancing system comprising:
a spring mechanism having a spring rate “k” coupled to the base support and an active connection point via a geometric constraining point, the active connection point located between the pivot point of the arm and the body and at a distance “d” from the pivot point, the geometric constraining point located a distance “h” from the pivot point; and
a cable guide system configured to support movement of a cable drive mechanism, the cable drive mechanism coupled at a first end to a second end of the spring mechanism and coupled at a second end to the active connection point,

wherein as the arm is rotated a force applied by the spring mechanism balances a gravitational torque of the arm to provide f=kX, where f is the force of the spring and x is a distance between the active connection point and the geometric constraining point.

2. The imaging apparatus as defined in claim 1 , wherein the spring mechanism provides a torque substantially equal to and in an opposite direction of the gravitational torque of rotating arm.

3. The imaging apparatus as defined in claim 1 , wherein as the arm is rotated a force applied by the spring mechanism balances the gravitational torque of the arm to provide k=mgl c /hd, where m is a mass of the body, g is a gravitational force and l c is a distance between the pivot point and the body.

4. The imaging apparatus as defined in claim 1 , wherein the cable guide system further comprises a first wheel and a second wheel configured to support movement of a cable drive mechanism.

5. The imaging apparatus as defined in claim 1 , wherein the geometric constraining point is configured as one of a cable routing point or a spring attachment point.

6. The imaging apparatus as defined in claim 1 , wherein the spring mechanism comprises a coil spring.

7. The imaging apparatus as defined in claim 1 , further comprising an extender arm configured in synchronous motion with the arm.

8. The imaging apparatus as defined in claim 1 , wherein the balancing system is disposed within the base support of the X-ray apparatus.

9. An X-ray apparatus, comprising:
a base support;
an arm having a first and a second end, an X-ray component coupled to one of the first and second end of the arm and defining a body having a mass “m”;
a rotating component pivotally coupled to the base support to provide rotation of the arm at a pivot point about an axis of rotation; and
a balancing system to balance a torque of the arm, the balancing system comprising:
a spring mechanism coupled to the base support at an inactive connection point and to an active connection point via a geometric constraining point, the active connection point located between the pivot point of the arm and the body and at a distance “d” from the pivot point, the geometric constraining point located a distance “h” from the pivot point,
an extender arm configured parallel to the arm and mounted to the rotating component for rotation relative to the base support; and
a cable guide system configured to support movement of a cable drive mechanism, the cable drive mechanism coupled at a first end to a second end of the spring mechanism and coupled at a second end to the active connection point on the extender arm,

wherein as the arm is rotated the balancing system maintains the same order of magnitude of an angle of rotation of the arm and an angle of rotation of the extender arm, and
wherein as the arm is rotated a force applied by the spring mechanism balances a gravitational torque of the arm to provide f=kX, where f is the force of the spring, k is a spring rate of the spring mechanism and x is a distance between the active connection point and the geometric constraining point.

10. The X-ray apparatus as defined in claim 9 , wherein as the arm is rotated a force applied by the spring mechanism balances a torque of the arm to provide k=mgl c /hd, where k is a spring rate of the spring mechanism, g is gravity, and l c is a distance between the pivot point and the body.

11. The X-ray apparatus as defined in claim 9 , wherein the spring mechanism comprises a coil spring comprising one of an extension spring, a compression spring, or an extension drawbar spring.

12. The X-ray apparatus as defined in claim 9 , wherein the arm, the rotating component and the extender arm rotate about a single axis of rotation.

13. The X-ray apparatus as defined in claim 9 , wherein the balancing system is disposed within the base support of the X-ray apparatus.

14. The X-ray apparatus as defined in claim 13 , wherein the balancing apparatus and the arm are configured on opposed sides of a vertical wall structure of the base support.

15. The X-ray apparatus as defined in Claim 9 , wherein the apparatus is a mammography system.

16. A mammography system, comprising:
a base support;
an arm coupled to a rotating component for rotating a body having a mass “m” about a pivot point relative to the base support about an axis of rotation, the rotating component coupled to the base support;
an extender arm configured parallel to the arm and coupled to the rotating component for rotating relative to the base support about the axis of rotation; and
a balancing system comprising:
a spring mechanism coupled to the base support and to an active connection point located on the extender arm between the axis of rotation of the arm and the body via a geometric constraining point, the active connection point located a distance “d” from the pivot point, the geometric constraining point located a distance “h” from the pivot point; and
a cable guide system configured to support movement of a cable drive mechanism, the cable drive mechanism coupled at a first end to a second end of the spring mechanism and coupled at a second end to the active connection point,

wherein as the arm is rotated about the axis of rotation, the balancing system synchronizes the angle of rotation of the arm with the angle of rotation of the extender arm such that the applied force of the spring mechanism counteracts the torque force of the arm to statically balance the system and provide f=kX, where f is the force of the spring, k is a spring rate of the spring mechanism and x is a distance between the active connection point and the geometric constraining point.

17. The mammography system of claim 16 , wherein as the arm is rotated a force applied by the spring mechanism balances the gravitational torque of the arm to provide k=mgl c /hd, where g is a gravitational force and l c is a distance between the axis of rotation and the body.

18. The mammography system of claim 16 , wherein the spring mechanism comprises a coil spring.

19. The mammography system of claim 16 , wherein a torque applied by the balancing system is selected to counteract the torque generated by the arm.

20. The mammography system of claim 16 , wherein the balancing system is disposed within a base support of the X-ray apparatus.

Assignees

• Gen Electric

Inventors

• Mao Ying
• Moulin Romain

Classifications

• F16M11/04

  Means for attachment of apparatus; Means allowing adjustment of the apparatus relatively to the stand · CPC title

• A61B6/447

  the source unit or the detector unit being mounted to counterpoise or springs · CPC title

• A61B6/502 Primary

  for diagnosis of breast, i.e. mammography · CPC title

• A61B6/4441 Primary

  the rigid structure being a C-arm or U-arm · CPC title