Light barrier or light grid with alignment mechanism

• US 7,087,884 B2
• Filed: 02/16/2005
• Issued: 08/08/2006
• Est. Priority Date: 02/19/2004
• Status: Expired due to Fees

• Current Assignee: Sick AG (Sick)
• Original Assignee: Sick AG (Sick)
• Inventors: Fetzer, Guenter, Wuestefeld, Martin, Rieger, Daniel
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): LIVEDALEN, BRIAN J
• Application Number:
  US11/060,245
• Publication Number:
  US 20050184225A1
• Time in Patent Office: 538 Days
• Field of Search: 250/221, 250/225, 340/555, 340/556, 340/557, 356/152.1, 356/153, 356/141.1
• US Class Current: 250/221
• CPC Class Codes: F16P 3/144 using light grids
• CPC Class Codes: G01V 8/20 using multiple transmitters or receivers

Abstract

A light barrier or light grid which has at least one light emitter arranged in a first housing and at least one associated light receiver arranged in a second housing. At least one emitter of visible alignment light installed in the first or the second housing generates one or more alignment light beams which is used to geometrically orient the light emitter relative to the opposite light receiver. For optically aligning the two housings, at least one alignment mechanism is present in the housing which receives the alignment beam. The alignment mechanism has at least one surface which optically deflects the alignment beam towards a target plane.

Claims

1. A light barrier comprising a light emitter arranged in a first housing, a light receiver arranged in a second housing operatively coupled with the light emitter, a visible alignment beam emanating from one of the first or second housings for optically aligning the first and second housings, an alignment mechanism in the other one of the first and second housings arranged to be struck by the alignment beam and including a surface which optically deflects the alignment beam, and a target plate, also located in the other one of the first and second housings, arranged to receive the alignment beam from the surface, said target plate having a surface configured so that the alignment beam diffusively scatters when impinging on said target plate.

2. A light barrier according to claim 1 wherein the target plate is arranged at an angle of about 45°

to a light entry surface of the other one of the housings.

3. A light barrier according to claim 1 wherein the target plate is on an inside floor of the other one of the housings.

4. A light barrier according to claim 1 wherein the target plate includes annular and/or cross-shaped lines arranged about a nominal target point for the alignment beam.

5. A light barrier according to claim 1 wherein the alignment mechanism extends along an axis of the other one of the housings which is perpendicular to the alignment beam from the one of the housings.

6. A light barrier according to claim 1 wherein the surface which optically deflects the alignment beam and the target plate of the alignment mechanism are formed by an optically transparent prism.

7. A light barrier according to claim 1 including a closure plate for the other one of the housings through which the alignment beam enters the other one of the housings, and through which an impact point of the alignment beam on the target plate can be observed.

8. A light barrier according to claim 1 wherein the target plate is integrally formed on an inside floor of the other one of the housings.

9. A light barrier according to claim 1 wherein the target plate has a shape of a two-dimensional, position-resolving reception element.