Machine element or mechanism – Gearing – Directly cooperating gears
Reexamination Certificate
2000-12-28
2003-05-27
Fenstermacher, David (Department: 3682)
Machine element or mechanism
Gearing
Directly cooperating gears
Reexamination Certificate
active
06568293
ABSTRACT:
TECHNICAL FIELD
The present invention relates to apparatus for producing linear motion, and more particularly to producing linear motion from rotary motion.
BACKGROUND ART
Linear motion can be produced using a large number of different mechanisms, and a wide range of such mechanisms will be apparent to those skilled in the art. Furthermore, a wide range of mechanisms which more specifically convert a rotary motion into a linear motion will also be known, and have found application in many different technical fields.
SUMMARY OF THE INVENTION
It is an object of the present invention that linear motion needs to be created with very simply controlled apparatus without requiring complicated gearing or switching systems. The linear motion is to be produced from rotary motion in a single direction.
In order to meet the above object, the present invention provides for an elongate drive rod of circular cross-section which is arranged to be rotated at a constant speed in the same direction. A carriage which is arranged to be mounted on the rod for axial movement along the length of the rod is provided with at least one roller member disposed with its axis of rotation at an angle to the perpendicular to the axis of rotation of the rod, and arranged to be pressed into contact with the surface of the rod by an actuator. The rotary motion of the rod causes the roller member to rotate about its axis, the direction of rotation causing a component vector to arise in an axial direction along the rod, thereby moving the carriage and roller along the elongate rod.
According to the present invention, there is provided an apparatus for producing linear motion comprising:
an elongate rod of circular cross-section arranged to be continuously rotated in a first direction about an elongate axis; and
a carriage arranged to be mounted on the rod so as to permit axial movement of the carriage along the length of the rod;
wherein the carriage comprises:
at least one first roller member arranged to contact the rod such that an axis of rotation of said roller member is at a first angle to the axis of rotation of the rod; and
at least one first actuator means for pressing the first roller member against the rod to cause rotation of the roller member;
wherein the rotation of the roller member generates at least one axial vector in a first axial direction along said rod whereby to cause axial movement of the carriage along the rod in said first axial direction.
The carriage may be further provided with at least one other roller member arranged to contact the rod at a second angle to the axis of rotation of the rod. In this case, the other roller member is provided with its own actuator means arranged to press the other roller member against the rod. The second angle at which the other roller member is disposed with respect to the axis of rotation of the rod is such so as to generate a second vector component in a second axial direction opposite to the first axial direction, thus moving the carriage in the opposite direction along the rod.
The second angle at which the other roller member is disposed at with respect to the angle of rotation of the rod may be identical in magnitude but opposite in direction to the first angle, in which case the speed of movement in each direction along the rod when the respective first or other roller is engaged with the rod will be identical. Alternatively, the second angle may be different in magnitude to the first angle, in which case the carriage will move at a different speed in the second axial direction when the other roller is engaged with the rod to the speed of movement in the first axial direction when the first roller is engaged with the rod.
Preferably, the operations of the first and the other actuation means are mutually exclusive, whereby only one or other of the roller members may be in contact with the rod at any one time.
Furthermore, the roller members need not each contact the same side of the rod, but may instead be disposed at any convenient location around the rod. In the case where the first roller is disposed on the opposite side of the rod to the other roller, then when the apparatus is viewed directly from above the first roller and the other roller may appear to be arranged at substantially the same angle to the axis of rotation of the rod. This is due to the actual contact surface of the rod effectively moving in opposite directions on each opposite side, thus generating axial vectors along the rod in opposite directions for the same roller angle.
It is advantageous if the means for pressing the rotatable members against the rod is in the form of a piezo electric device so that the linear motion can be electrically controlled.
In addition, more than one roller member may be provided arranged to generate movement in each direction. In this case, each roller member arranged to generate movement in the same direction may be disposed at different angles to each other, so that the speed of linear movement of the carriage in the direction may be varied by selection of the appropriate roller. Furthermore, where this is the case, the actuator means for each roller can be controlled independently from each other.
REFERENCES:
patent: 402674 (1889-05-01), Judson
patent: 2382105 (1945-08-01), Sarver
patent: 3425284 (1969-02-01), Shelton
patent: 3599498 (1971-08-01), Misenti
patent: 3717042 (1973-02-01), Zaruba
Patent Abstracts of Japan, vol. 12, No. 374 (M-749), Oct. 16, 1988, and Japanese Patent Publication No. 63-125855 A, to Sumitomo Heavy Ind. Ltd., May 30, 1988.
Patent Abstracts of Japan, vol. 14, No. 274 (P-1061), Jun. 13, 1990, and Japanese Patent Publication No. 2-80907 A, to Mitsutoyo Corp., Mar. 22, 1990.
Patent Abstracts of Japan, vol. 14, No. 274 (P-1061), Jun. 13, 1990, and Japanese Patent Publication No. 2-80908 A, to Mitsutoyo Corp., Mar. 22, 1990.
Fenstermacher David
PBT ( IP) Limited
Rankin, Hill Porter & Clark LLP
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