Balanced orbital sander/grinder
AssigneeFesto AG & Co.
InventorsPeter Maier, Horst Haberhauer
Life of this patent
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Abstract
An orbital sander/grinder has on one side of its housing a rotatably mounted disk holder which is brought into orbital motion by means of a drive mechanism that is inside the housing, and is coupled with an eccenter. The eccenter is rotatably mounted on one side in the housing, on the other side in the disk holder, while the rotational axis in the housing is radially offset relative to the rotational axis of the eccenter in the disk holder, but the two axes run parallel to each other. A balancing weight for compensating the unbalance rotates in synchronization with the eccenter. To ensure sanding/grinding with a minimum of vibration, means are provided to compensate for the transverse forces generated by the abrasive and/or cutting forces that are exerted at the eccenter.
Claims12
Operationally balanced orbital grinding or sanding machine having
- a housing (1);
- a grinding or sanding disk holder (3) movably retained on the housing adapted to hold a grinding or sanding disk;
- a drive shaft (4) rotatably retained in the housing at right angles with respect to the grinding or sanding disk holder and defining a shaft axis of rotation;
- an eccentric (8) secured to the shaft (4), said eccentric being rotatable about, and defining, an eccentric axis (9), parallel to and spaced from the shaft axis of rotation, and coupled to said grinding or sanding disk holder;
- a balancing weight means (16) rotating in synchronism with the eccentric (8) and having an axis of rotation at least approximately coincident with the shaft axis of rotation to compensate eccentric unbalanced forces relative to the housing generated by the eccentric and the grinding or sanding disk holder (3) coupled thereto upon rotation of the drive shaft (4),
- wherein, in order to automatically compensate for a transverse rotating force vector (27) arising from the cutting or grinding force effect between a grinding or sanding surface of the grinding or sanding disk secured to the disk holder (3), and a workpiece,
- said balancing weight means (16) is so positioned with respect to the eccentric axis of rotation (9) and so dimensioned that said weight means, in operation, exerts forces to balance said cutting force vector (27), said weight means acting on the eccentric axis of rotation (9) in a direction at right angles with respect to a theoretical connecting line (25a) between the shaft axis of rotation (7) and the eccentric axis of rotation (9) said weight means (16) having a center of gravity (29) being asymmetrically positioned with respect to said theoretical connecting line (25a).
Dependencies are inferred from the claim text.