Method of and apparatus for conveying object by utilizing vibration
AssigneeHitachi, Ltd.
InventorsKenji Mori, Hiromu Hirai, Isao Kobayashi, Tomoko Kumagae, Muneo Kawamoto
Life of this patent
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Abstract
A vibrating-type driving unit employing a piezo-electric device is provided for conveying an object such as a sheet material. A follower roller is provided to be opposed to the vibrating-type driving unit, and A.C. power is supplied thereto so as to convey the object. In addition, a friction coefficient of surface of the follower roller is selected to be greater than friction coefficient of a driving head of the vibrating-type driving unit. With this selection, it is possible to convey the object efficiently and stably.
Claims16
An apparatus for conveying an object, comprising:
- a piezoelectric driving unit which generates a vibration having an amplitude on an order of several .mu.m at an end surface of a driving head by application of an A.C. voltage;
- a rotating member arranged to be opposed to said driving head of said piezoelectric driving unit and supported for rotation about its axis in a direction in which said object is conveyed, wherein said rotating member has a surface such that a frictional coefficient .mu..sub.1 between said driving head and said object and a frictional coefficient .mu..sub.2 between said rotating member and said object satisfy a relationship of .mu..sub.1 <.mu..sub.2 ;
- pressure applying means for applying pressure to a portion of said object which is present in a gap between said piezoelectric driving unit and said rotating member when said object is being passed through said gap;
- and
- a power source for supplying electric power to said piezoelectric driving unit.
An apparatus for conveying an object comprising:
- a roller disposed for rotation about its axis in a direction of travel of said object to be conveyed;
- a vibrating-type driving unit having a driving head disposed at a location opposing said roller;
- object-presence detecting means for detecting whether or not said object is present in or near a gap between said roller and said driving head;
- and
- relay means for cutting off supply of electric power to said vibrating-type driving unit for a period during which absence of said object is detected by said object-presence detecting means.
An apparatus for conveying an object, comprising:
- a vibrating-type driving unit to generate a vibration at an end surface of a driving head by application of an A.C. voltage;
- a roller arranged to be opposed to said driving head of said vibrating-type driving unit and supported for rotation about its axis in a direction in which said object is conveyed;
- pressure applying means for applying to said object pressure large enough to enable said object to be conveyed by rotational force of said roller when said object is present between said roller and said vibrating-type driving unit;
- speed detecting means for detecting speed of conveyance of said object;
- and
- a driving circuit to calculate a difference between a desired speed and said speed of conveyance detected by said speed detecting means and then to regulate electric power to be supplied to said vibrating-type driving unit so as to offset said difference.
An apparatus for conveying an object, comprising:
- a vibrating-type driving unit;
- a rotating member supported for rotation about its axis and cooperating with said vibrating-type driving unit to define a gap slightly smaller than thickness of said object;
- a power source for supplying electric power to said vibrating-type driving unit;
- position detecting means for detecting present position of said object to be conveyed;
- and
- a controller for controlling supply of electric power to said vibrating-type driving unit in accordance with a difference between said present position and a desired position to which said object should be conveyed.
In a method of controlling a piezoelectric motor which is adapted to generate a circular locus in a piezoelectric driving unit incorporating a piezoelectric device to thereby drive a driven member brought into contact with said piezoelectric driving unit, a method of conveying an object characterized in that, in a case of long-stroke driving, rough driving is effected by utilizing vibration created by applying a high-frequency voltage across said piezoelectric device and in that, in a case of positioning, fine driving is effected by utilizing a small displacement created by applying D.C. voltage across said piezoelectric device, and in that, the timing for said positioning being set as a timing at which the value of a difference with respect to said desired position reaches a value not greater than any value which corresponds to the inside of the maximum stroke of a driving member on account of applying D.C. voltage across said piezoelectric device.
Dependencies are inferred from the claim text.