Four square test device with torque stabilization

Claim 2

A test stand device comprising means for testing at least two rotating specimens dynamically, first means mechanically connecting first ends of said specimens for rotation simultaneously with respect to each other while each specimen is under torque, second means mechanically connecting the second ends of said specimens for rotation simultaneously, drive means to rotate said specimens, said second means including rotating torque transmitting members, means coupling said specimens to the rotating torque transmitting members, said coupling means comprising actuators to control torque level between said specimens and said rotating torque transmitting members and including means for substantially simultaneously adjusting the actuators to change the torque carried by each of said specimens without transmitting the torque change through said first means from one specimen to the other.

Claim 3

The combination as specified in claim 1 wherein said actuator means comprise fluid pressure actuator means, servo valve means to control the level of torque transmitted by said fluid pressure actuator means, and load cell means sensing the torque level of said specimens to provide a control signal for said servo valve means.

Claim 4

The combination as specified in claim 1 wherein said first means comprises a pair of gears drivably connected together to transmit torque between the first ends of said specimens.

Claim 5

The combination as specified in claim 1 wherein there are four specimens comprising four shafts, and wherein said shafts are coupled in pairs end to end to form two pairs of shafts with each pair comprising two shafts in series, and wherein said first means and second means are connected between the pairs of shafts.

Claim 6

A test stand device comprising means for simultaneously changing the torque in a four square test system without subjecting the test specimens to inertial loads from the connecting drive means comprising at least one pair of specimens arranged in substantially side by side relationship, first mechanical torque transmitting drive means drivably connecting first ends of said specimens, second torque transmitting drive means drivably connecting second ends of said specimens, said second torque transmitting drive means comprising a pair of rotating drive members drivably coupled together and separate fluid pressure actuator means connected between each of said specimens and said drive members, said fluid pressure actuator means being operably connected to transmit torque between said specimens and said drive members, servo valve means to control said fluid pressure actuator means whereby changes in torque in the specimens can be made through said fluid pressure actuator means substantially simultaneously to each of said specimens without being transmitted from one specimen to the other through said first mechanical torque transmitting drive means, and means to rotate said specimens.

Claim 7

A test stand device comprising means for simultaneously changing the torque in a four square test system without subjecting the test specimens to inertial loads from the connecting drive means comprising at least one pair of specimens arranged in substantially side by side relationship, first mechanical torque transmitting drive means drivably connecting first ends of said specimens, second torque transmitting drive means drivably connecting second ends of said specimens, said second torque transmitting drive means comprising a pair of rotating drive members drivably coupled together and separate fluid pressure actuator means connected between each of said specimens and said drive members, said fluid pressure actuator means being operably connected to transmit torque between said specimens and said drive members, servo valve means to control said fluid pressure actuator means whereby changes in torque in the specimens can be made through said fluid pressure actuator means substantially simultaneously to each of said specimens without being transmitted from one specimen to the other through said first mechanical torque transmitting drive means, and means to rotate said specimens.

Claim 8

The combination as specified in claim 5 wherein each of said fluid pressure actuator means comprise rotary actuators, said rotary actuators having first and second elements, one of said elements being connected to the actuator''s associated specimen and the other said elements being connected to its associated drive member, sensing means to determine the angle between said first and second elements relative to a reference position, and control means to provide equal relative deflection of said first and second elements of each of said fluid pressure actuators relative the reference position.

Claim 9

The combination as specified in claim 5 wherein said fluid pressure actuators comprise servo valve actuated hydraulic rotary actuators.

Claim 10

The combination as specified in claim 7 and hydraulic coupling means for transmitting hydraulic fluid under pressure to said actuators while said specimens are rotating.

Claim 11

The combination as specified in claim 5 wherein said first torque transmitting drive means comprise spur gear members drivably engaging each other, and cOnnected to the respective specimens.

Claim 12

The combination as specified in claim 9 and load cell means in each of said shaft means, and said load cell means being coupled to provide a signal proportional to the torque transmitted by each of the said specimens, and means to control the torque transmitted by each of said fluid pressure actuator means in response to signals from said load cell means.

Claim 13

The combination as specified in claim 10 and control means responsive to said load cell means to maintain the force transmitted by said fluid pressure actuator means at a preselected level.

Claim 14

In a four square specimen testing device comprising a plurality of test specimens to be subjected to torque arranged in a series-parallel system comprising two sets of specimens, a set of first gear drive means between first ends of said specimens, power means to rotate said specimens, wherein the improvement comprises means to transmit torque between second ends of said test specimens comprising rotating torque transmitting drive means and separate rotary hydraulic actuators connected to each of the sets of specimens and being separately and simultaneously actuable, said hydraulic actuators each including first and second elements, means to introduce fluid pressure into said hydraulic actuators while said specimens are rotating, a first of said elements of each of said hydraulic actuators being connected to one respective set of specimens and a second element of each of said hydraulic actuators being connected to the torque transmitting drive means for its associated set of specimens, and means to determine the amount of torque being carried by each of said sets of specimens, means controlling said hydraulic actuators to be operable to introduce torque changes into each of the sets of the specimens independently of the said drive connection at the first ends from fluid pressure acting between the first and second elements of that actuator.

Claim 15

In a four square specimen testing device comprising a plurality of test specimens to be subjected to torque arranged in a series-parallel system comprising two sets of specimens, a set of first gear drive means between first ends of said specimens, power means to rotate said specimens, wherein the improvement comprises means to transmit torque between second ends of said test specimens comprising rotating torque transmitting drive means and separate rotary hydraulic actuators connected to each of the sets of specimens and being separately and simultaneously actuable, said hydraulic actuators each including first and second elements, means to introduce fluid pressure into said hydraulic actuators while said specimens are rotating, a first of said elements of each of said hydraulic actuators being connected to one respective set of specimens and a second element of each of said hydraulic actuators being connected to the torque transmitting drive means for its associated set of specimens, and means to determine the amount of torque being carried by each of said sets of specimens, means controlling said hydraulic actuators to be operable to introduce torque changes into each of the sets of the specimens independently of the said drive connection at the first ends from fluid pressure acting between the first and second elements of that actuator.