Fastener inspection system

• US 20050155915A1
• Filed: 12/30/2003
• Published: 07/21/2005
• Est. Priority Date: 12/30/2003
• Status: Active Grant

• Current Assignee: Zen Voce Manufacturing Pte., Ltd. (Zen Voce Corporation)
• Original Assignee: Zen Voce Manufacturing Pte., Ltd. (Zen Voce Corporation)
• Inventors: Mah, Ta Seng Jeffrey, Ong, Hock Seh
• Granted Patent: US 7,364,043 B2
• Time in Patent Office: Days
• US Class Current: 209/561
• CPC Class Codes: B07C 5/10 measured by light-responsive means sorting according to colour B07C5/342
• CPC Class Codes: B07C 5/365 using a single separation means
• CPC Class Codes: G01N 2021/95615 with stored comparision signal
• CPC Class Codes: G01N 21/9515 Objects of complex shape, e.g. examined with use of a surface follower device measuring contours and curvatures G01B11/24
• CPC Class Codes: G01N 21/952 Inspecting the exterior surface of cylindrical bodies or wires G01N21/956 takes precedence
• CPC Class Codes: Y10S 209/919 Rotary feed conveyor
• CPC Class Codes: Y10S 209/92 Vibratory feed conveyor
• CPC Class Codes: Y10S 209/938 Illuminating means facilitating visual inspection
• CPC Class Codes: Y10S 209/939 Video scanning

Abstract

A high-speed fastener inspection system is provided to perform 100 percent inspection of various geometry features and to sort a large number of fasteners at high speed. The inspection system includes a rotary table having an outer periphery, an inner periphery, and a plurality of radial slots extending from the outer periphery to the inner periphery. When a fastener is be placed in a radial slot with the head of the fastener facing upward and the shank extending into the slot, the side view of each fastener is unobstructed. A loading mechanism, an anti-jam mechanism, and a sorting mechanism are arranged along the outer periphery of the rotary table. At least one vision inspection camera is provided for capturing the image of each fastener after each fastener is placed in a radial slot. An image analyzer is operatively connected to the vision inspection camera for analyzing the captured image and to determine whether the fastener is defective. Once the defective fastener has been identified by the image analyzer, the sorting mechanism is actuated to remove the defective fastener from the rotary table.

Claims

1. An inspection system for inspecting and sorting a plurality of fasteners, each fastener having a head and a shank, said system comprising:

a rotary table having an outer periphery, an inner periphery, and a plurality of radial slots extending from the outer periphery to the inner periphery, each radial slot being configured to receive a fastener with the head of the fastener facing upward and to shank suspending in the radial slot;

means for rotating the rotary table;

a loading mechanism for sequentially delivering the fasteners to the radial slots;

an anti-jam mechanism for preventing jamming as the fasteners are being delivered to the radial slots;

at least one vision inspection camera operable to capture an image of each fastener after the fastener has been delivered to a radial slot;

an image analyzer operatively connected to said at least one vision inspection camera for analyzing the captured image and to determine whether the fastener shown in the captured image is defective; and

a sorting mechanism for removing any defective fastener from the rotary table when the defective fastener has been identified by the image analyzer,

wherein the loading mechanism, the anti-jam mechanism and the sorting mechanism are positioned along the outer periphery of the rotary table.

2. The inspection system of claim 1 further comprising:

a sweeper positioned along the outer periphery of the rotary table at a location between the loading mechanism and the sorting mechanism; and

an acceptance chute positioned adjacent to the sweeper,

wherein the sweeper is adapted for sweeping the non-defective fasteners from the rotary table into the acceptance chute.

3. The inspection system of claim 1, wherein two side-view inspection cameras are provided, one of the cameras being closer to the outer periphery of the rotary table than the other, and the image analyzer is operatively connected to both side-view inspection cameras.

4. The inspection system of claim 1, wherein said side-view inspection cameras capture unobstructed image of each said fastener after the fastener has been delivered to a radial slot.

5. The inspection system of claim 1, wherein a top-surface inspection camera is provided for inspecting the top surface of each fastener.

6. The inspection system of claim 1, wherein the unloading mechanism comprises:

a linear track with a discharge slot for guiding the fasteners toward the rotary table, said linear track having a downstream end that is positioned adjacent to the outer periphery of the rotary table, and said discharge slot having a width that is smaller than the head diameter of each fastener but greater than the diameter of the shank;

a track top cover mounted on the linear track for covering the discharge slot; and

a stopper positioned adjacent to the downstream end of the linear track so as to prevent each fastener from moving toward the inner periphery of the rotary table after each fastener has been transferred into a radial slot.

7. The inspection system of claim 6, wherein the anti-jam mechanism comprises an anti-jam arm positioned adjacent to the linear track, the anti-jam arm having a curved edge positioned adjacent to the outer periphery of the rotary table, and the anti-jam arm being spring-loaded so that the curved edge can retract away from the outer periphery of the rotary table when the fasteners are jammed.

8. The inspection system of claim 1, wherein the sorting mechanism comprises:

an air-jet supplier for blowing the defective fastener from the rotary table; and

a reject chute positioned adjacent to the air-jet supplier for receiving the defective fastener.

9. The inspection system of claim 1, wherein the rotary table is provided with a plurality of support plates radially arranged on the rotary table so that a spacing is defined between adjacent support plates, each spacing having a width that is smaller than the diameter of the head of each fastener but greater than the diameter of the shank, and each spacing being aligned with each radial slot in a manner that enable the heads of the fasteners to rest on the support plates while the shanks extend into the radial slots.

10. The inspection system of claim 1 further comprising:

a vibratory supply bowl for supplying a plurality of fasteners; and

a pair of parallel guide rails defining a transfer slot there between,

wherein the parallel guide rails are arranged between the vibratory supply bowl and the loading mechanism so that the fasteners may be sequentially fed from the vibratory supply bowl along the transfer slot to the loading mechanism.

11. The inspection system of claim 1 further comprising a light for illuminating each fastener as said at least one vision inspection camera is capturing the side view image of the fastener.

12. A method for automatically inspecting and sorting a plurality of fasteners, said method comprising:

providing an inspection system comprising;

(a) a rotary table having an outer periphery, an inner periphery, and a plurality of radial slots extending from the outer periphery to the inner periphery, each radial slot being configured to receive a fastener;

(b) means for rotating the rotary table;

(c) a loading mechanism for sequentially delivering the fasteners to the radial slots;

(d) an anti-jam mechanism for preventing jamming as the fasteners are being delivered to the radial slots;

(e) at least one vision inspection camera operable to capture a side view image of each fastener after the fastener has been delivered to a radial slot;

(f) an image analyzer operatively connected to said at least one vision inspection camera for analyzing the captured image and to determine whether the fastener shown in the captured image is defective; and

(g) a sorting mechanism for removing any defective fastener from the rotary table when the defective fastener has been identified by the image analyzer;

inspecting a plurality of fasteners using said inspection system; and

separating any defective fastener from the inspected fasteners.

13. The method of claim 12, wherein each fastener has a head and a shank.

14. A method for automatically inspecting and sorting a plurality of fasteners, said method comprising:

providing a rotary table having an outer periphery, an inner periphery, and a plurality of radial slots extending from the outer periphery to the inner periphery, each radial slot being configured to receive a fastener;

rotating the rotary table;

sequentially delivering a plurality of fasteners into the radial slots, one fastener per slot;

operating at least one vision inspection camera to capture an unobstructed side-view image of each fastener after each fastener has been delivered to a radial slot;

analyzing the captured image to determine whether the fastener shown in the captured image is defective;

removing any defective fastener from the rotary table when the defective fastener has been identified; and

collecting the non-defective fasteners on the rotary table.