Disclosed is a hand-held electric tool, in which a main shaft (1) swings back and forth around an axis (11) to drive accessories (9) of the tool to carry out various types of operations. A swing device is provided with an eccentric element (41) capable of reducing the shock caused to a shell (7) by a connecting rod component (3). Another shell (6) is provided with a valve device (5) used for adjusting the flow of air current in different air ducts. The accessories (9) of the tool can be cooled or cleaned through the air current in one of the air ducts. The main shaft (1) is provided with an elastic support (2) used for balancing the load when an electrical motor (8) is operating. The elastic support (2) can replace a bearing in supporting the main shaft (1) swinging back and forth around the axis (11).

A parallel link mechanism includes: a base including guide members; moving bodies capable of moving along the guide members; a fixed link having a base end portion fixed to the base and extending in a direction away from the base; a turning body being connected to a distal end portion of the fixed link and being turnable around the distal end portion; and movable links having base end portions connected to the moving bodies and distal end portions connected to the turning body and causing the turning body to turn along with movement of the moving bodies, the guide members being inclined so as to get closer to the turning body as the guide members get farther away from the center portion of the base main body.

A parallel link mechanism includes: a base including guide members; moving bodies capable of moving along the guide members; a fixed link having a base end portion fixed to the base and extending in a direction away from the base; a turning body being connected to a distal end portion of the fixed link and being turnable around the distal end portion; and movable links having base end portions connected to the moving bodies and distal end portions connected to the turning body and causing the turning body to turn along with movement of the moving bodies, the guide members being inclined so as to get closer to the turning body as the guide members get farther away from the center portion of the base main body.

An apparatus and adjustable apparatus, for translating movement of a rotating shaft to rotational movement in two dimensions of a lever arm including a first frame and a second frame, a first shaft rotatably connected to the first frame and arranged for rotation about a first axis of rotation, a lever having a fulcrum, wherein the fulcrum is arranged within the second frame and arranged for pivoting about a second axis of rotation, wherein the second axis of rotation is coplanar with the first axis of rotation, wherein the second frame is rotatably connected to the first frame, the second frame arranged for rotation with respect to the first frame about a third axis of rotation, wherein the third axis of rotation is arranged perpendicularly and spaced apart from the first axis of rotation, wherein the first, second, and third axes have single point of intersection.

An apparatus and adjustable apparatus, for translating movement of a rotating shaft to rotational movement in two dimensions of a lever arm including a first frame and a second frame, a first shaft rotatably connected to the first frame and arranged for rotation about a first axis of rotation, a lever having a fulcrum, wherein the fulcrum is arranged within the second frame and arranged for pivoting about a second axis of rotation, wherein the second axis of rotation is coplanar with the first axis of rotation, wherein the second frame is rotatably connected to the first frame, the second frame arranged for rotation with respect to the first frame about a third axis of rotation, wherein the third axis of rotation is arranged perpendicularly and spaced apart from the first axis of rotation, wherein the first, second, and third axes have single point of intersection.

An apparatus and adjustable apparatus, for translating movement of a rotating shaft to rotational movement in two dimensions of a lever arm including a first frame and a second frame, a first shaft rotatably connected to the first frame and arranged for rotation about a first axis of rotation, a lever having a fulcrum, wherein the fulcrum is arranged within the second frame and arranged for pivoting about a second axis of rotation, wherein the second axis of rotation is coplanar with the first axis of rotation, wherein the second frame is rotatably connected to the first frame, the second frame arranged for rotation with respect to the first frame about a third axis of rotation, wherein the third axis of rotation is arranged perpendicularly and spaced apart from the first axis of rotation, wherein the first, second, and third axes have single point of intersection.

An apparatus and adjustable apparatus, for translating movement of a rotating shaft to rotational movement in two dimensions of a lever arm including a first frame and a second frame, a first shaft rotatably connected to the first frame and arranged for rotation about a first axis of rotation, a lever having a fulcrum, wherein the fulcrum is arranged within the second frame and arranged for pivoting about a second axis of rotation, wherein the second axis of rotation is coplanar with the first axis of rotation, wherein the second frame is rotatably connected to the first frame, the second frame arranged for rotation with respect to the first frame about a third axis of rotation, wherein the third axis of rotation is arranged perpendicularly and spaced apart from the first axis of rotation, wherein the first, second, and third axes have single point of intersection.