Conveyors: power-driven – Conveyor system for moving a specific load as a separate unit – System includes an oscillating or reciprocating load...
Reexamination Certificate
1999-07-27
2001-02-20
Ellis, Christopher P. (Department: 3651)
Conveyors: power-driven
Conveyor system for moving a specific load as a separate unit
System includes an oscillating or reciprocating load...
C198S468400, C198S750100, C198S750120
Reexamination Certificate
active
06189680
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a rotary conveyor, more precisely relates to a rotary conveyor in which a rotating section can be turned without twisting and entangling electric cables, air tubes, etc.
In some conventional automatic machining lines, rotary conveyors are employed. The rotary conveyor intermittently conveys work pieces in a circumferential direction.
In the conventional rotary conveyor, a plurality of holding units, which are capable of respectively holding the work pieces, are provided in a rotating section with regular angular separations (an angle SA). The rotating section is intermittently turned the angle SA prescribed times so as to intermittently index and convey the work pieces. By employing the rotary conveyor, a plurality of steps for machining the work pieces can be executed simultaneously. The work pieces which have been completely machined are discharged in order. The rotary conveyor can efficiently machine the work pieces. Note that, the rotating section is intermittently and endlessly rotated in one direction only.
A wafer polishing machine disclosed in JP Pat. No. 2501763, which includes the conventional rotary conveyor, will be explained with reference to FIG.
3
. The polishing machine polishes outer circumferential faces of wafers.
The polishing machine includes: a rotating section
50
capable of intermittently rotating a prescribed angle; a plurality of swing arms
51
being provided in the rotating section
50
with regular angular separations; a plurality of holding units
52
, which are capable of respectively holding the wafers
60
and each of which is provided to a front end of each of the swing arms
51
; a wafer loading station
53
which is located at a position corresponding to one of stop positions of the swing arms
51
; a first polishing station
54
and a second polishing station
55
which respectively have rotary polishing units for polishing the wafers
60
; a wafer unloading station
56
; and swing drive units
57
, which are respectively provided to the first and second polishing stations
54
and
55
and each of which turns the swing arm
51
located in the polishing station so as to press the outer circumferential face of the wafer
60
, which has been held by the holding unit
52
, to the rotary polishing unit. Note that, the holding units
50
include means for holding the wafers
60
by air suction, and the holding units
52
holding the wafers
50
can be rotated by rotary drive units
58
.
However, in the conventional rotary conveyor, the rotating section is endlessly rotated in one direction only and electric devices and/or pneumatic devices are mounted on the rotating section, so slip rings and/or rotary joints must be required so as to prevent twisting and cutting electric cables and/or air tubes. Namely, the slip rings are used to maintain electric connection and the rotary joints are used to maintain air communication, even if the rotating section is endlessly rotated in the one direction only. By employing the slip rings and rotary joints, a structure of the conventional rotary conveyor must be complex.
Further, in the case of the conventional rotary conveyor for a complex machine, the number of poles of the slip rings must be limited, so a control unit including a sequence must be mounted on the rotating section.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a rotary conveyor which has a simple structure and is capable of preventing an electric cable and/or an air tube from twisting and cutting.
To achieve the object, the rotary conveyor of the present invention comprises:
a base section;
a rotating section being capable of relatively rotating, with respect to the base section, in the both directions about a center shaft thereof;
a drive unit for rotating the rotating section in the both directions;
a number N (N is an integer three or more) of movable stations being provided on the rotating section with regular angular separations, each of which is an angle &thgr;1, the movable stations respectively machining work pieces; and
the number N of fixed stations being provided on the base section, the fixed stations being located at positions corresponding to the movable stations, the fixed stations respectively machining the work pieces with the movable stations,
wherein the rotating section is intermittently turned the angle &thgr;1 a prescribed number (N−1) of times, in one direction, from an initial position of the rotating section, then the rotating section is continuously turned, in the other direction, until reaching the initial position. By the action of the rotating section, twisting and cutting the cables and tubes can be prevented without slip rings and rotary joints, so the structure of the rotary conveyor can be simpler.
In the rotary conveyor, each of the movable stations may have a holding unit capable of holding the work piece. With this structure, despite each of the movable stations holds the work piece only once, the work piece can be continuously machined in a plurality of the steps.
In the rotary conveyor, one of the fixed stations may be capable of loading and unloading the work pieces. With this structure, efficiency of machining the work pieces can be improved.
In the rotary conveyor, each of the movable stations may have a machining unit for machining the work piece, and each of the fixed stations may have a holding unit capable of holding the work piece. With this structure, the rotary conveyor can be employed in an automatic machining machine.
In the rotary conveyor, each of the movable stations may have an electric device, to which an electric cable is connected. With this structure, twisting and cutting the electric cable can be prevented.
In the rotary conveyor, each of the movable stations may have a pneumatic device, to which an air tube is connected. With this structure, twisting and cutting the air tube can be prevented.
In the rotary conveyor, each of the movable stations may have an electric device, to which an electric cable is connected, and a pneumatic device, to which an air tube is connected. With this structure, twisting and cutting the electric cable and air tube can be prevented.
REFERENCES:
patent: 5085312 (1992-02-01), Ribordy et al.
patent: 5906261 (1999-05-01), Kok et al.
patent: 5921375 (1999-07-01), Van Laar
patent: 2501763 (1996-03-01), None
Ellis Christopher P.
Fujikoshi Kikai Kogyo Kabushiki Kaisha
Jordan and Hamburg LLP
Tran Khoi H.
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