Single bus DC control circuit

Claim 2

A DC control circuit comprising: a bus bar; a primary circuit including a DC voltage source of high and low positive and of high and low negative voltage, selector means operatively connected between said bus bar and said voltage source for selectively applying said high or low positive or negative voltage to said bus bar; f a secondary circuit including collector means for making electrical contact with said bus bar and a voltage polarity and voltage level responsive circuit operatively connected to said collector means including polarity means for producing an output condition indicative of the polarity of voltage applied to said bus bar and voltage level means for producing an output condition indicative of a said high or low voltage applied to said bus bar and; means responsive to the operation of said secondary circuit for operating a device in a mode corresponding to said polarity means output condition and at a rate corresponding to said voltage level means output condition.

Claim 3

The circuit of claim 1, wherein said polarity means includes first and second branch circuits connected in parallel with said collector means, said voltage level means including a third branch circuit connected in parallel with said first and second branch circuits, first, second and third relay coils being connected in series in the respective branch circuits, said third relay coil being operable only by a high voltage level on said bus bar, said first and second branch circuits including respectively in series with said first and second relay coils normally closed relay contacts operated respectively by said second and first relay coils, said first branch circuit including in series with said first relay coil a first diode connected to be forward-biased by the application of positive voltage to said bus bar, said second branch circuit including in series with said second relay coil a second diode connected to be forward-biased by the application of negative voltage to said bus bar, said first and second branch circuits each including identical parallel subcircuits having one path with a pair of normally closed relay contacts operated by said third relay coil and an alternate path with a resistor in series with a pair of normally open relay contacts operated by said third relay coil, said resistor being sized to compensate for the difference between high and low voltage levels to achieve equivalent energization of the first or second relay coil respectively, at either voltage level.

Claim 4

The circuit of claim 2, wherein said third branch circuit includes a resistor in series with said third relay coil sized to enable operative energization of said third relay coil only by said high voltage level.

Claim 5

The circuit of claim 3, wherein said first, second and third relay coils are interchangeably identical.

Claim 6

The circuit of claim 2, wherein said voltage source includes a pair of high and low positive voltage terminals and a pair of high and low negative voltage terminals, said selector means including four pairs of normally open switch contacts respectively connecting said terminals in parallel to said bus bar and third, fourth, fifth and sixth diodes respectively connected to be forwarded-biased by said respective terminals between said bus bar and each pair of said switch contacts.

Claim 7

The circuit of claim 5, wherein said primary circuit further includes first and second push-button break-before-make switch means corresponding respectively to voltage polarity each having two discrete levels of depression including means for making a low voltage circuit with a first pair of said normally open contacts at a first level of depression and, with further depression to the second level, breaking the low voltage circuit and then making a high voltage circuit of the same polarity with a second pair of normally open switch contacts.

Claim 8

The circuit of claim 6, wherein each pair of said third, fourth, fifth and sixth diodes interconnected with terminals of the same polarity is connected in common via a pair of normally closed safety switch contacts to said bus bar, said push-button switch means having means for keeping the normally closed safety contacts for the opposite polarity open at either level of depression.

Claim 9

A single bus traveling crane DC control circuit comprising: bus bar means for providing electrification for a moving crane element; a primary manually operable control circuit including a multilevel dual polarity DC voltage source with a pair of high and low positive voltage terminals and a pair of high and low negative voltage terminals, selector circuit means interconnected with said voltage source for applying DC voltage of a selected level and polarity to said bus bar means; a secondary circuit movable relative to said primary circuit and adapted to be operatively interconnected with said crane element, including collector means for making moving electrical contact with said bus bar means and a voltage polarity and voltage level responsive circuit operatively connected to said collector means including polarity means for producing an output condition indicative of the polarity of voltage applied to said bus bar means and voltage level means for producing an output condition indicative of a high or low voltage applied to said bus bar means; and means responsive to the operation of said secondary circuit for operating said crane element in a mode corresponding to said polarity means output condition and at a rate corresponding to said voltage level means output condition.

Claim 10

A single bus traveling crane DC control circuit comprising: bus bar means for providing electrification for a moving crane element; a primary manually operable control circuit including a multilevel dual polarity DC voltage source with a pair of high and low positive voltage terminals and a pair of high and low negative voltage terminals, selector circuit means interconnected with said voltage source for applying DC voltage of a selected level and polarity to said bus bar means; a secondary circuit movable relative to said primary circuit and adapted to be operatively interconnected with said crane element, including collector means for making moving electrical contact with said bus bar means and a voltage polarity and voltage level responsive circuit operatively connected to said collector means including polarity means for producing an output condition indicative of the polarity of voltage applied to said bus bar means and voltage level means for producing an output condition indicative of a high or low voltage applied to said bus bar means; and means responsive to the operation of said secondary circuit for operating said crane element in a mode corresponding to said polarity means output condition and at a rate corresponding to said voltage level means output condition.

Claim 11

The circuit of claim 8, wherein said polarity means includes first and second branch circuits connected in parallel with said collector means, said voltage level means including a third branch circuit connected in parallel with said first and second branch circuits, first, second and third relay coils being connected in series in the respective branch circuits, said third relay coil being operable only by a high voltage level on said bus bar means, said first and second branch circuits including respectively in series with said first and second relay coils normally closed relay contacts operated respectively by said second and first relay coils, said first branch circuit including in series with said first relay coil a first diode connected to be forward-biased by the application of positive voltage to said bus bar means, said second branch circuit including in series with said second relay coil a second diode connected to be forward-biased by the application of negative voltage to said bus bar means, said first and second branch circuits each including identical parallel subcircuits having one path with a pair of normally closed relay contacts operated by said third relay coil and an alternate path with a resistor in series with a pair of normally open relay contacts operated by said third relay coil, said resistor being sized to compensate for the difference between high and low voltage levels to achieve equivalent energization of the first or second relay coil, respectively, at either voltage level.

Claim 12

The circuit of claim 9, wherein said third branch circuit includes a resistor in series with said third relay coil sized to enable operative energization of said third relay coil only by said high voltage level.

Claim 13

The circuit of claim 10, wherein said first, second and third relay coils are interchangeably identical.

Claim 14

The circuit of claim 9, wherein said voltage source includes a pair of high and low positive voltage terminals and a pair of high and low negative voltage terminals, said selector means including four pairs of normally open switch contacts respectively connecting said terminals in parallel to said bus bar means, and third, fourth, fifth and sixth diodes respectively connected to be forward-biased by said respective terminals between said bus bar means and each pair of said switch contacts.

Claim 15

The circuit of claim 12, wherein said primary circuit further includes first and second push-button break-before-make switch means corresponding respectively to voltage polarity each having two discrete levels of depression for making a low voltage circuit with a first pair of said normally open contacts at a first level of depression and, with further depression to the second level, breaking the low voltage circuit and then making a high voltage circuit for the same polarity with a second pair of said normally open switch contacts.

Claim 16

The circuit of claim 13, wherein each pair of said third, fourth, fifth and sixth diodes interconnected with terminals of the same polarity is connected in common via a pair of normally closed safety switch contacts to said bus bar means, said push-button switch means having means for keeping the normally closed safety contacts for the opposite polarity open at either level of depression.

Claim 17

A DC control circuit comprising: a DC voltage source of high and low positive and of high and low negative voltage; a power line; means for selectively applying said DC high and low positive or said DC high and low negative voltage to said line; a circuit electrically connected to said line including polarity means for producing an output condition indicative of the polarity of voltage applied to said line and voltage level means for producing an output condition indicative of a high or low voltage applied to said line; and means responsive to the operation of said circuit for operating a device in a mode corresponding to said polarity means output condition and at a rate corresponding to said voltage level means output condition.

Claim 18

A DC control circuit comprising: a DC voltage source of high and low positive and of high and low negative voltage; a power line; means for selectively applying said DC high and low positive or said DC high and low negative voltage to said line; a circuit electrically connected to said line including polarity means for producing an output condition indicative of the polarity of voltage applied to said line and voltage level means for producing an output condition indicative of a high or low voltage applied to said line; and means responsive to the operation of said circuit for operating a device in a mode corresponding to said polarity means output condition and at a rate corresponding to said voltage level means output condition.