Configurable counterbalance mechanism
Implementations relate to a configurable counterbalance mechanism. In some implementations, a counterbalance apparatus includes a spring, a tension element coupled between the spring and a mechanical ground, a base element coupled to a load, and a configurable arm rotatably coupled to the base element. A first pulley and a second pulley are rotatably coupled to the configurable arm, the second pulley orbitable about the first axis, and the tension element is at least partially wrapped around the first pulley and the second pulley. The configurable arm is rotatably configurable at either a first orientation or a second orientation, where the first orientation is associated with a center of gravity of the load located on a first side of the counterbalance apparatus and the second orientation is associated with the center of gravity of the load located on a second side of the counterbalance apparatus opposite to the first side.
1 . A counterbalance apparatus comprising:
a spring;
a tension element including a first end coupled to the spring and a second end coupled to a mechanical ground;
a base element rigidly coupled to a load;
a configurable arm rotatably coupled to the base element, the configurable arm being rotatable about a first axis; and
one or more pulleys rotatably coupled to the configurable arm,
wherein a particular pulley of the one or more pulleys is orbitable about the first axis;
wherein the tension element is at least partially wrapped around the one or more pulleys;
wherein the configurable arm is rotatably configurable about the first axis at a first orientation and a second orientation; and
wherein the first orientation is associated with a center of gravity of the load located on a first side of the counterbalance apparatus, and the second orientation is associated with the center of gravity of the load located on a second side of the counterbalance apparatus opposite to the first side.
2 . The counterbalance apparatus of claim 1 , wherein:
the particular pulley is rotatable about a second axis.
3 . The counterbalance apparatus of claim 2 , wherein:
the configurable arm and the particular pulley are positioned such that a third axis intersects the first axis, the second axis, and the center of gravity of the load.
4 . The counterbalance apparatus of claim 2 , wherein:
the configurable arm includes a length; and
the length is aligned with a third axis that intersects the first axis, the second axis, and the center of gravity of the load.
5 . The counterbalance apparatus of claim 2 , wherein:
the counterbalance apparatus further includes a first stop member associated with the first orientation of the configurable arm and a second stop member associated with the second orientation of the configurable arm;
the first stop member is located in a path of clockwise rotation of the configurable arm about the first axis; and
the second stop member is located in a path of counterclockwise rotation of the configurable arm about the first axis.
6 . The counterbalance apparatus of claim 1 , wherein:
the configurable arm is rotatably configurable to the first orientation and to the second orientation independently from an orientation of the load with respect to the counterbalance apparatus.
7 . The counterbalance apparatus of claim 1 , further comprising a rotatable shaft having a length and an axis of rotation about the length, wherein:
the base element is a joint gear rigidly coupled to the rotatable shaft;
the configurable arm is rotatably coupled to the rotatable shaft; and
an axis of rotation of the particular pulley is offset from the axis of rotation of the rotatable shaft.
8 . The counterbalance apparatus of claim 1 , wherein:
the base element includes a first slot and a second slot;
the configurable arm engages with the first slot at the first orientation of the configurable arm without engaging with the second slot; and
the configurable arm engages with the second slot at the second orientation of the configurable arm without engaging with the first slot.
9 . The counterbalance apparatus of claim 8 , wherein:
the configurable arm includes a plug portion;
the plug portion includes first tapered sides;
the first slot of the base element includes one or more second tapered sides;
the second slot of the base element includes one or more third tapered sides; and
the first tapered sides of the plug portion are engageable with the one or more second tapered sides of the first slot and with the one or more third tapered sides of the second slot of the base element.
10 . The counterbalance apparatus of claim 1 , wherein:
the configurable arm includes a first aperture, and the first aperture includes a threaded portion and a clearance portion;
the base element includes a second aperture; and
the counterbalance apparatus further includes a bolt extending through the particular pulley, through the first aperture of the configurable arm, and into the second aperture of the base element.
11 . The counterbalance apparatus of claim 1 , wherein:
the first orientation of the configurable arm counterbalances the center of gravity of the load located on the first side of the counterbalance apparatus; and
the second orientation of the configurable arm counterbalances the center of gravity of the load located on the second side of the counterbalance apparatus.
12 . The counterbalance apparatus of claim 1 , wherein:
the tension element is a cable.
13 . The counterbalance apparatus of claim 1 , wherein:
the particular pulley is a first pulley;
the one or more pulleys further include a second pulley rotatably coupled to the configurable arm and rotatable about the first axis, and a third pulley rotatably coupled to the mechanical ground;
the tension element is wrapped at least partially around the third pulley prior to being wrapped around the first pulley in a path from the first end to the second end of the tension element; and
the third pulley has an axis of rotation that is fixed in a same position relative to the second pulley at both the first orientation and the second orientation of the configurable arm.
14 . The counterbalance apparatus of claim 1 , wherein the configurable arm is:
fixed in rotation with reference to the base element when at the first orientation and when at the second orientation, and
rotatable between the first orientation and the second orientation with respect to the base element when at an orientation of the configurable arm other than the first orientation and the second orientation.
15 . The counterbalance apparatus of claim 2 , wherein:
the particular pulley is a first pulley;
the counterbalance apparatus further includes a curved element that includes a curved surface, the curved element coupled to the mechanical ground;
the one or more pulleys further include a second pulley and a third pulley;
the second pulley is rotatable about the first axis;
the third pulley is rotatably coupled to the curved element and is rotatable about a third axis of rotation that is nonparallel to the first axis and the second axis;
in a path from the first end to the second end of the tension element, the tension element is wrapped at least partially around the third pulley prior to being wrapped around the first pulley, and the tension element is at least partially wrapped around the curved element prior to being coupled to the mechanical ground at the second end of the tension element; and
along the path from the first end to the second end of the tension element, the tension element exits contact with the third pulley and enters contact with the curved surface of the curved element at points located within a plane that intersects the second pulley and the first pulley.
16 . The counterbalance apparatus of claim 15 , wherein:
the plane is orthogonal to the first axis and the second axis; and
the third axis of rotation is at a non-orthogonal angle with reference to the plane.
17 . The counterbalance apparatus of claim 15 , wherein:
the curved element is rigidly coupled to the mechanical ground, is centered on the third axis, and is located between the third pulley and the mechanical ground; and
the curved surface of the curved element has a radius equal to a radius of the third pulley.
18 . The counterbalance apparatus of claim 15 , further comprising a fourth pulley rotatably coupled to the mechanical ground and rotatable about a fourth axis, wherein:
the tension element is wrapped at least partially around the fourth pulley prior to being wrapped around the third pulley in the path from the first end to the second end of the tension element; and
the fourth axis is nonparallel to the first axis, the second axis, and the third axis.
19 . The counterbalance apparatus of claim 1 , wherein:
the configurable arm includes an edge and a slot in the edge; and
the slot is configured to receive a separation tool to slide or pry the configurable arm away from the base element.
20 . The counterbalance apparatus of claim 1 , wherein:
the counterbalance apparatus is included in a component of a teleoperated surgical system.