Conveyors: power-driven – Conveyor section – Reciprocating conveying surface
Reexamination Certificate
1999-06-23
2001-04-03
Bidwell, James R. (Department: 3651)
Conveyors: power-driven
Conveyor section
Reciprocating conveying surface
C198S750100
Reexamination Certificate
active
06209713
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a part transfer apparatus, and more particularly, to an apparatus for aligning and intermittently conveying parts.
2. Description of the Related Art
Hitherto, small parts, such as chip parts, have been transferred by, for example, a method in which parts are caused to slide down along a downwardly inclined groove for guiding parts by using potential energy, a method in which parts are fed by air pressure using compressed air or negative pressure, or a method in which an endless belt that forms a bottom face of a groove for conveyance is intermittently driven (e.g., Japanese Unexamined Patent Publication No. 8-48419).
The slide-down method has low reliability because parts are sometimes caught during travel due to contaminants thereon or static electricity. Although the air method simplifies the structure, it is sensitive to pressure changes. Furthermore, since an air pressure source is required, the cost is increased. In contrast, the belt drive method has a relatively high reliability, whereas a drive mechanism for intermittently driving the belt is complicated, and durability is apt to be lowered.
Accordingly, the present inventors have proposed a transfer apparatus that does not significantly damage parts and that provides high reliability and a simple structure (Japanese Patent Application No. 10-111671). The Japanese Patent Application No. 10-111671 has not been published yet. This transfer apparatus comprises a guide groove for aligning and transferring parts, a conveyor member placed at the bottom of the guide groove so as to move forward and backward in the direction of the groove, and a driving means for reciprocally driving the conveyor member so that the reverse speed of the conveyor member is higher than the advance speed, and the transfer apparatus conveys parts by using the difference in frictional force.
In such a transfer apparatus, a cam that is turned in one direction is provided as the driving means, a spring is provided to urge the conveyor member backward, and the rear end of the conveyor member is made to contact the peripheral surface of the cam, whereby the conveyor member can be reciprocally driven on the above-described condition. In this case, the structure of the driving means is substantially simplified, and the motion of the conveyor member can be freely set by changing the cam curve.
Since the cam and the conveyor member are in direct contact with each other, however, the force perpendicular to the moving direction of the conveyor member acts on the conveyor member, thereby vibrating the conveyor member vertically. This vibration lifts parts placed on the conveyor member, and thereby impairs transfer efficiency. Furthermore, since the amount of sliding between the peripheral surface of the cam and the conveyor member is large, and the conveyor member is pressed against the peripheral surface of the cam by the spring, both the members may undergo serious wear.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a part transfer apparatus that prevents vibration and wear of a conveyor member, and that achieves high transfer efficiency.
In order to achieve the above object, according to an aspect of the present invention, there is provided a part transfer apparatus, including a guide groove for aligning and guiding parts; a conveyor member disposed at the bottom of the guide groove so as to move forward and backward in the direction of the groove; and a driving means for conveying parts laid on the top face of the conveyor member forward by reciprocally driving the conveyor member so that the speed of backward movement is higher than the speed of forward movement, wherein the driving means includes a cam to be turned in a fixed direction, a pivoting cam lever in contact with the peripheral surface of the cam so as to convert the displacement of the peripheral surface of the cam into the forward and backward movement of the conveyor member, and a spring for urging the conveyor member or the cam lever backward.
When the cam is turned in a fixed direction, the cam lever runs onto a higher portion of the cam, the cam lever pivots forward, and the conveyor member engaged with the cam lever advances at low speed. For this reason, parts laid on the top face of the conveyor member are carried forward together with the conveyor member by the holding frictional force that acts between the conveyor member and the parts. When the cam turns further and the cam lever drops to a low portion of the cam, the cam lever pivots backward at high speed. Thereby, the conveyor member also reverses at high speed. Since the speed of reversing is higher than that of advancing, the parts slip relative to the conveyor member, only the conveyor member reverses, and the parts are held at the advanced position.
Since the cam lever is interposed between the cam and the conveyor member, the force perpendicular to the moving direction of the conveyor member hardly acts on the conveyor member, whereby the vertical vibration of the conveyor member is limited. This makes it possible to prevent parts laid on the conveyor member from being lifted, and to thereby improve transfer efficiency. Furthermore, since the conveyor member and the cam lever slide with respect to each other by a small amount, wear can be reduced, compared with a case in which the cam and the conveyor member are in direct contact with each other. By changing the contact point between the cam lever and the conveyor member, the stroke of the conveyor member can be changed even when the same cam is used, which provides a high degree of freedom of design.
In order to convert the displacement of the peripheral surface of the cam into forward and backward movement of the conveyor member via the cam lever, preferably, a spring is provided to urge the conveyor member backward so that the rear end of the conveyor member is made to contact the front side of the cam lever by the urging force of the spring. In this case, the structure is substantially simplified.
Preferably, one of the cam lever and the conveyor member has an engaging pin, the other has an engaging hole to be slidably engaged with the engaging pin, and a spring is provided to pivotally urge the cam lever backward. In this case, since a spring for urging the conveyor member backward is not required, load is not imposed on the connecting portion between the engaging pin and the engaging hole, which prevents the connecting portion from wear.
Further objects, features, and advantages of the present invention will become apparent from the following description of the preferred embodiments with reference to the attached drawings.
REFERENCES:
patent: 1565664 (1968-03-01), None
patent: 672352 (1952-05-01), None
patent: 8-48419 (1996-02-01), None
Kaishita Nihei
Nemoto Akira
Takahashi Shigeki
Bidwell James R.
Burns Doane , Swecker, Mathis LLP
Murata Manufacturing Co. Ltd.
LandOfFree
Part transfer apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Part transfer apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Part transfer apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2496472