Conveyors: power-driven – Conveyor section – Live roll
Reexamination Certificate
1999-11-16
2001-08-07
Valenza, Joseph E. (Department: 3651)
Conveyors: power-driven
Conveyor section
Live roll
C198S788000, C198S867130
Reexamination Certificate
active
06269941
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a roller conveyor for conveying elongated articles such as skids used, for example, in an automobile painting line.
2. Description of the Related Art
Conventionally, in an equipment or line for painting the bodies of automobiles, in order to prevent mutual collision between the adjacent automobile bodies during conveyance, each automobile body to be painted is placed on a skid having a length larger than the length of the automobile body. The automobile body carried on the skid is then conveyed by a roller conveyor A
1
such as shown in FIG.
7
.
The roller conveyor A
1
includes an elongated rectangular conveyor frame A
2
disposed on a floor surface, a number of flanged free rollers A
3
disposed on and along one longitudinal edge of the conveyor frame A
2
, and a number of drive rollers A
4
disposed on and along the other longitudinal edge of the conveyor frame A
2
at respective positions corresponding to the positions of the flanged free rollers A
3
.
Each of the flanged free rollers A
3
is freely rotatable about a horizontal axis and has a pair of annular flanges F, F at opposite ends of an outer peripheral surfaces thereof. The annular flanges F, F serve to guide opposite side surfaces of an roller engagement portion t which is provided at the bottom of one skid leg A
6
of a skid A
5
on which a work W is carried. The outer peripheral surface of the flanged free roller A
3
supports an undersurface of the roller engagement portion t of the skid A
5
.
Each of the drive rollers A
4
has an outer peripheral surface on which the undersurface of a roller engagement portion t of the other skid leg A
6
of the same skid A
5
is supported. The drive roller A
4
is driven in rotation by the built-in drive motor, so that the skid A
5
is conveyed on the roller conveyor A
1
.
The skid to be conveyed by the roller conveyor is preferably constructed as light as possible so as to improve the conveyance efficiency and the thermal efficiency during conveyance through a drying furnace with a painted automobile body carried on the skid. Additionally, the skid generally has an elongated structure having a length of 5 to 6 meters and a width of about 800 millimeters. Accordingly, the skid of the foregoing construction is likely to be distorted when subjected to a load during conveyance or manufacture thereof.
Due to the distortion of the skid, the roller engagement portion on the skid leg of the skid being conveyed on the roller conveyor may disengage from the outer peripheral surface of the drive roller. Thus, the drive roller fails to transmit a sufficient driving force to the skid, lowering the conveyance efficiency of the roller conveyor.
Particularly in the case of a roller conveyor including a succession of free rollers each disposed between two adjacent ones of the drive rollers, it may occurs that the roller engagement portion of the skid is in contact with one free roller alone while separating from the adjacent drive roller, thereby disenabling further conveyance of the skid.
To cope with this problem, at least one longitudinal edge of the conveyor frame which is adapted to face the corresponding skid leg must be equipped exclusively with the drive rollers. This arrangement, however, requires an increased number of drive rollers, makes the conveyor roller complicated in construction, and increases the manufacturing cost of the conveyor roller.
SUMMARY OF THE INVENTION
It is accordingly an object of the present invention to provide a conveyor roller used for conveyance of an elongated article, which requires only a small number of drive rollers, is relatively simple in construction, and can be manufactured at a low cost.
To accomplish the above-mentioned object, the present invention provides a roller conveyor for conveying an elongated article including a roller engagement portion having a length, the roller conveyor comprising a row of drive roller units arranged in a conveyance direction of the elongated articles at intervals which are smaller than the length of the roller engagement portion of the elongated article. Each of the drive roller units includes a fixed member, a drive roller for frictionally driving the elongated article in the longitudinal direction thereof while engaging the roller engagement portion of the elongated article, a floating support frame rotatably supporting thereon the drive roller and being attached to the fixed member so as to enable an outer peripheral surface of the drive roller to move toward and away from the roller engagement portion of the elongated article, and an urging means for urging the floating support frame in a direction to force the outer peripheral surface of the drive roller against the roller engagement portion.
Preferably, the roller conveyor further includes at least one freely rotatable idler roller disposed between each adjacent pair of the drive roller units for bearing part of a load on the elongated article at a fixed position.
It is also preferable that the roller conveyor further includes a row of freely rotatable idler rollers arranged in parallel with said row of drive roller units for bearing part of a load on the elongated article at a fixed position. At least a part of the idler rollers has an outer peripheral surface formed with a guide portion for guiding the engagement portion of the elongated article to prevent meandering of the elongated article during conveyance.
With this construction, the elongated article, such as a skid, is conveyed as the respective drive rollers of plural drive roller units are rotated while they are in contact with the roller engagement portion of the elongated article.
During conveyance, even when a path of movement of the roller engagement portion is caused to change or fluctuate due to distortion of the elongated article, the floating support frame while being urged by the urging means automatically follows up the change in moving position of the roller engagement portion. Accordingly, the drive roller is always kept in rolling engagement with the roller engagement portion with the result that a frictional driving force of the drive roller is surely transmitted to the elongated article.
In the case where at least one freely rotatable idler roller is provided between each adjacent pair of the drive roller units for bearing part of a load on the elongated article at a fixed position, the load on the elongated article is partially born or supported by the idler roller and thus lessen the load on the drive roller and floating support frame of the drive roller unit.
Furthermore, in the case where the roller conveyor further a row of freely rotatable idler rollers arranged in parallel with said row of drive roller units for bearing part of a load on the elongated article at a fixed position wherein at least a part of the idler rollers has an outer peripheral surface formed with a guide portion for guiding the engagement portion of the elongated article to prevent meandering of the elongated article during conveyance, it becomes possible to reduce the number and size of the drive rollers used and to achieve stable, meandering-free conveyance of the elongate article, such as a skid having a given width, by the use of a reduced number of down-sized drive rollers.
The above and other objects, features and advantages of the present invention will becomes apparent to these versed in the art upon making reference to the following detailed description and accompanying sheets of drawings in which a preferred structural embodiment incorporating the principle of the present invention is shown by way of illustrative example.
REFERENCES:
patent: 2077189 (1937-04-01), Rishel
patent: 2216504 (1940-10-01), Sekulski
patent: 2608286 (1952-08-01), Henschker
patent: 3511489 (1970-05-01), Field
patent: 3690440 (1972-09-01), MacPherson
Dann Dorfman Herrell and Skillman
Skillman Henry H.
Tsubakimoto Chain Co.
Valenza Joseph E.
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