1. A relay device adapted to be positioned in a transmission system for transmitting a video signal from a source device to a sink device, the relay device comprising:
a video signal receiving unit that receives the video signal from the source device;
a video signal transmitting unit that transmits the video signal to the sink device;
a first communication unit that receives a first message regarding a power supply capability of the sink device;
a second communication unit that transmits a second message regarding a power supply capability of the relay device to the source device;
a first power circuit that receives power supplied by the sink device; and
a second power circuit that supplies power to the source device;
wherein an amount of sum of the power supply capability of the relay device and power consumed at the relay device does not exceed an amount of power supply capability of the sink device, and
wherein an amount of power to be supplied from the second power circuit to the source device is arranged to be difference between an amount having been supplied from the sink device to the first power circuit and another amount consumed at the relay device.
2. The relay device according to claim 1, wherein the amount of power having been consumed at the relay device comprises amounts of power consumed at both the video signal receiving unit and the video signal transmitting unit; and
wherein the first power circuit is arranged to transmit, to the source device, information on power supply capability of the relay device having been changed in response to other information on change of power supply capability of the sink device.
3. A method for transmitting a video signal from a source device to a sink device using a relay device, the method comprising:
receiving, at the relay device, the video signal from the source device;
transmitting, by the relay device, the video signal to the sink device;
receiving, at the relay device, a first message regarding a power supply capability of the sink device;
transmitting, by the relay device, a second message regarding a power supply capability of the relay device to the source device;
receiving, at the relay device, power supplied by the sink device; and
transmitting, by the relay device, power to the source device;
wherein an amount of sum of the power supply capability of the relay device and power consumed at the relay device does not exceed an amount of power supply capability of the sink device, and
wherein an amount of power to be supplied from the second power circuit to the source device is arranged to be difference between an amount having been supplied from the sink device to the first power circuit and another amount consumed at the relay device.
4. The method according to claim 3, wherein the amount of power having been consumed at the relay device comprises amounts of power consumed at both the video signal receiving unit and the video signal transmitting unit; and
wherein the first power circuit is arranged to transmit, to the source device, information on power supply capability of the relay device having been changed in response to other information on change of power supply capability of the sink device.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
We claim:
1. Apparatus adapted for gripping an object, comprising a mounting head; suction-operated gripping means for selectively gripping an object positioned adjacent one side of said gripping means; suction-operated attaching means for selectively and removably attaching said gripping means to said mounting head, whereby said gripping means is removable from said mounting head and is hence replaceable; and viewing means, including a camera, for viewing an object gripped by said gripping means, said viewing means being located on an opposite side of said gripping means, said gripping means having a light-transmitting portion positioned in such a manner that an object gripped by said gripping means can be viewed by said camera through said gripping means, and said camera being independently and selectively movable relative to said mounting head.
2. The apparatus of claim 1, further comprising first supplying means for selectively and independently supplying suction to said attaching means and second supplying means for selectively and independently supplying suction to said gripping means.
3. The apparatus of claim 2, wherein said attaching means includes a vacuum transfer plate mounted to said mounting head, said vacuum transfer plate including a groove having a side open towards said gripping means such that suction can be applied from said first supplying means to said gripping means through said groove.
4. The apparatus of claim 3, wherein said vacuum transfer plate includes a first suction channel formed through said vacuum transfer plate and communicating with said groove, said first suction channel being connected to said first supplying means.
5. The apparatus of claim 4, wherein said light-transmitting portion is positioned in the field of view of said camera.
6. The apparatus of claim 5, wherein said gripping means includes a chuck having a second suction channel through said light-transmitting portion for gripping an object in response to application of suction from said second supplying means through said second suction channel.
7. The apparatus of claim 6, wherein said second supplying means includes a third suction channel extending through said vacuum transfer plate, said third suction channel communicating with said second channel for supplying suction to said second suction channel through said third suction channel.
8. The apparatus of claim 7, wherein said viewing means includes a mirror for reflecting the image of an object gripped by said gripping means to said camera, said mirror being movable conjointly with said camera relative to said mounting head.
9. The apparatus of claim 8, wherein said viewing means includes a housing for housing said camera and said mirror.
10. The apparatus of claim 1, wherein said viewing means includes a mirror for reflecting the image of an object gripped by said gripping means to said camera, said mirror being movable conjointly with said camera relative to said mounting head.
11. The apparatus of claim 10, wherein said viewing means includes a housing for housing said camera and said mirror.