Torque controlled power roller for conveyor system

Claim 2

A low-profile power roller mechanism for propelling movable objects along a supporting surface comprising: a drive roller, means mounting said roller adapted selectively to position the roller in a lowered condition entirely below the plane of the supporting surface so as to be out of contact with the object or in an elevated condition with its periphery tending to encroach into the plane of the supporting surface so as to be in traction with the object, a source of rotary power, means transmitting rotary motion from said power source to the roller to drive the same, and means including a torque element operated by said power source to shift said roller from a lowered condition to said elevated condition and to impose a lifting force on the roller proportional to the driving force on the roller required to move the object, and means for limiting the shifting movement of said roller substantially beyond said elevated condition.

Claim 3

A mechanism as defined in claim 1 in which the means to shift and impose a lifting force on the roller includes a cam, and means between the torque element an the cam to turn the latter.

Claim 4

A mechanism as defined in claim 2 in which the means to shift and impose a lifting force on the roller includes a planetary gear set, and the torque element is a ring gear in the gear set free to turn a limited amount.

Claim 5

A mechanism as defined in claim 2 in which the means transmitting rotary motion includes a reduction gear train.

Claim 6

A mechanism as defined in claim 3 in which the means transmitting rotary motion includes a cage in the planetary set coupled with a reduction gear train.

Claim 7

A mechanism as defined in claim 1 in which the means mounting the roller includes a stationary frame, and a secondary frame, a pivotal mounting supporting a portion of the secondary frame on the stationary frame enabling a portion of the secondary frame removed from the pivotal mounting to rise or fall, the roller being journaled in the last named portion of the secondary frame.

Claim 8

A mechanism as defined in claim 6 in which the means to shift and impose a lifting force on the roller includes a cam, and means between the torque element and the cam to turn the latter.

Claim 9

A mechanism as defined in claim 7 in which the cam is journaled in the secondary frame, a cam roller is journaled in the stationary frame, and the cam rides on the cam roller.

Claim 10

A mechanism as defined in claim 8 in which a stop element is fixed in the stationary frame, and the cam embodies a latch portion adapted to engage the stop element to limit rotation of the cam and thereby limit action of the torque element.

Claim 11

A mechanism as defined in claim 9 in which the powEr source is reversible, and the cam is double lobed having a neutral position and turnable for either lobe to engage the cam roller.

Claim 12

A mechanism as defined in claim 3 in which the ring gear is disposed within a housing and its rotation is unrestrained by the latter, a transmission system couples the ring gear and the cam, the torque of the ring gear being delivered by the transmission system to actuate the cam, and means cooperating with the cam to restrict actuation thereof and retard or limit rotation of the ring gear.

Claim 13

A mechanism as defined in claim 11 in which a cage of the planetary gear set delivers rotary power to the drive roller when the ring gear is retarded or its rotation limited.

Claim 14

A power roller mechanism for propelling movable objects along a supporting surface comprising: a drive roller, means mounting said roller adapted selectively to position the roller in a lowered condition entirely below the plane of the supporting surface so as to be out of contact with the object or in an elevated condition with its periphery tending to encroach into the plane of the supporting surface so as to be in traction with the object, a source of rotary power, means transmitting rotary motion from said power source to the roller to drive the same, and means including a torque element operated by said power source to shift said roller from a lowered condition to an elevated condition and to impose a lifting force on the roller proportional to the driving force on the roller required to move the object, the means to shift and impose a lifting force on the roller including a cam, means between the torque element and the cam to turn the latter, a planetary gear set, the torque element being a ring gear in the gear set free to turn a limited amount, and means coupled with the roller to impose a resistance to rotation when the roller is out of contact with the object to be moved greater than resistance to rotation concurrently offered by the cam.

Claim 15

A power roller mechanism for propelling movable objects along a supporting surface comprising: a drive roller, means mounting said roller adapted selectively to position the roller in a lowered condition entirely below the plane of the supporting surface so as to be out of contact with the object or in an elevated condition with its periphery tending to encroach into the plane of the supporting surface so as to be in traction with the object, a source of rotary power, means transmitting rotary motion from said power source to the roller to drive the same, and means including a torque element operated by said power source to shift said roller from a lowered condition to an elevated condition and to impose a lifting force on the roller proportional to the driving force on the roller required to move the object, the means to shift and impose a lifting force on the roller including a cam, means between the torque element and the cam to turn the latter, a planetary gear set, the torque element being a ring gear in the gear set free to turn a limited amount, and means coupled with the roller to impose a resistance to rotation when the roller is out of contact with the object to be moved greater than resistance to rotation concurrently offered by the cam.

Claim 16

A mechanism as defined in claim 13, in which the last named means is a drag brake.

Claim 17

In a power roller mechanism for propelling loads along a platform having freely rotatable means for supporting such loads along a laterally extending plane thereon a rotatable drive roller having an axis disposed parallel to said plane, means for supporting said roller for translatory movement under power into, and for free gravitational movement out of a position in which it is tangential to said load plane and in tractional engagement with a load supported thereon comprising a pivotal mounting for said supporting means laterally displaced from said roller axis; said supporting means having its center of gravity located between said pivotal mounting and said roller axis whereby gravity is effective to normally maintain said roller out of its position tangential to said load plane and out of tractional engagement with a load supported thereon, power means effective upon operation to rotate said roller on its axis and to actuate said supporting means to cause the same to translate said roller into its position tangential to said load plane and in traction with a load supported thereon, and effective upon cessation of operation to permit gravitational return of said supporting means to remove said roller from said position.

Claim 18

In a power roller mechanism for propelling loads along a platform having freely rotatable means for supporting such loads along a laterally extending plane thereon a rotatable drive roller having an axis disposed parallel to said plane, means for supporting said roller for translatory movement under power into, and for free gravitational movement out of a position in which it is tangential to said load plane and in tractional engagement with a load supported thereon comprising a pivotal mounting for said supporting means laterally displaced from said roller axis; said supporting means having its center of gravity located between said pivotal mounting and said roller axis whereby gravity is effective to normally maintain said roller out of its position tangential to said load plane and out of tractional engagement with a load supported thereon, power means effective upon operation to rotate said roller on its axis and to actuate said supporting means to cause the same to translate said roller into its position tangential to said load plane and in traction with a load supported thereon, and effective upon cessation of operation to permit gravitational return of said supporting means to remove said roller from said position.

Claim 19

A power roller mechanism according to claim 15 in which the means operable by said drive train comprises gearing operable to concurrently supply rotational and translatory propulsion to said roller, and responsive to arrest of translation of said roller by a load supported by said supporting means to continue to supply rotational propulsion to said roller.

Claim 20

A power roller mechanism according to claim 16 in which said gearing includes a sun gear, planet gear and ring gear.

Claim 21

A power roller mechanism according to claim 16 including means for braking rotational movement of said roller in all positions thereof and in which said gearing is responsive to said braking means to supply translAtory propulsion to said roller to bring the same to said position tangential to said load plane.