Dobbies

Claim 2

A loom dobby for use in a weaving loom of the type which includes certain movable parts such, for example, as heald frames each movable up or down by a respective corresponding jack lever, the dobby comprising a plurality of units, each unit including one of said jack levers aforesaid and being operative to actuate one of said movable parts, an electric motor for each jack lever for moving the respective jack lever up or down between selected limits in accordance with a predetermined pattern to be produced in cloth to be woven, and means for transmitting motion from each respective motor to the corresponding jack lever and, in combination, control means including a programmed pattern device operative so to start and stop selective motors automatically as to change the position of the jack levers in accordance with the predetermined pattern.

Claim 3

A loom dobby according to claim 1, further characterized in that the movable parts are heald frames and the means for transmitting motion from each motor to its respective jack lever includes a crank wheel with a crankpin mounted thereon, a connecting rod for transmitting motion from the crankpin to the jack lever, and speed-reducing means for transmitting force from the motor to the crank wheel.

Claim 4

A loom dobby according to claim 2, in which the limiting positions, up or down of each jack lever, correspond to the two diametrically opposed dead centers of the corresponding crankpins.

Claim 5

A loom dobby according to claim 1, further characterized in that the programmed pattern means for each jack lever comprises a chain, each chain being made up of bowls and spacers in preselected order in accordance with the desired woven pattern, further characterized in that the control means includes a switch so arranged to respond differently to the passage of a bowl or a spacer on the chain to control the operation of one of said motors and thereby to determine which one of its limiting positions shall be occupied by the corresponding jerk lever.

Claim 6

A loom dobby according to claim 2, further characterized in that the control means includes a cam carried by each respective crank wheel, and a stop switch corresponding to each respective limiting position of each respective lever and which is responsive to said cam means for stopping the motor when the jack lever reaches either of said limiting positions.

Claim 7

A loom dobby according to claim 1, further characterized in that each of said motors is of a conventional type which includes a friction brake which is operative to stop the motor and the parts driven thereby when the motor circuit is broken as the jack lever Reaches a limiting position.

Claim 8

A loom dobby according to claim 1 in which the control means includes a timing cam adapted to close a timing switch in the control means and thereby to initiate the simultaneous starting of all the selected motors and subsequently, after the selected crankgears have completed their half-turns, to open said timing switch in readiness for the next selection and shedding operation, the jack levers meanwhile being retained in one or other of their limiting positions for a time sufficient to enable a weft pick to be passed through the shed defined by those heald frames which have been actuated by the selected jack levers.

Claim 9

A loom dobby according to claim 1, in which the control means includes automatic stop means operable to stop the loom in the case of faulty movement of any jack lever.

Claim 10

A loom dobby according to claim 7, further characterized in that the control means includes automatic stop means operable to stop the loom in the case of faulty movement of any jack lever, and in which the automatic stop means includes a master relay energizable through a master switch which is operated by the timing cam, such master relay when energized serving to enable an auxiliary relay for the selected jack levers to be energized and each jack lever having contacts in series with a stop relay such that the stop relay can be energized only when the contacts of the auxiliary relay are closed, the stop relay having contacts adapted to be situated such that when the stop relay is deenergized the loom is stopped, and also including bypass means whereby when the master relay is deenergized when the jack levers are stopped in one or other of their limiting positions, the auxiliary relays remain energized to prevent undesired stopping of the machine.

Claim 11

A loom dobby according to claim 9 including a warning light associated with each auxiliary relay which is connected to that relays contact to be illuminated if the relay is deenergized and a stop stop light arranged to be illuminated if the stop relay is deenergized.