Modular drive unit for a conveyor

Claim 2

In a combination for driving a conveyor of the endless belt type, an endless belt forming a loop having portions parallel to each other; a plurality of teeth carried by the endless belt along two spaced rows parallel to the direction of movement of the endless belt, a drive unit comprising first and second drive couplings for the first and second spaced rows of teeth, respectively, each of said drive couplings including two sprocket wheel means each having axially displaced rows of sprocket teeth and mounted for rotation about axes transverse to the path of the endless belt and longitudinally displaced from one anothEr along the path of the endless belt, the corresponding sprocket wheel means on the first and second drive couplings being axially aligned, said sprocket wheel means being mounted with the teeth on the sprocket wheel means overlapping yet transversely displaced with respect to the teeth carried by said endless belt, first and second loops of multiple-strand driving chain for said first and second drive couplings, respectively, each of said loops having alternate strands engaged by the teeth of its associated row of teeth on the endless belt and the teeth on its associated sprocket wheel means, and motive means mounted within the loop of said endless belt between said first and second drive couplings, said motive means being operative to impart rotational movement to a pair of axially aligned sprocket wheel means to drive said endless belt through said drive coupling whereby the necessity for means independent of the sprocket wheels to lift the driving chains into engagement with the teeth carried by the endless belt is eliminated.

Claim 3

The drive unit of claim 1 wherein said sprocket wheel means each comprise a pair of axially displaced rows of sprocket teeth, wherein said mounting means positions said sprocket wheel means so that the sprocket teeth of each pair of rows straddle the teeth carried by said endless belt and wherein said multiple strand driving chain is a three strand chain with the side strands being engaged by the corresponding row of sprocket teeth on each sprocket wheel means while the center strand engages the teeth carried by the endless belt.

Claim 4

The combination of claim 2 wherein the teeth carried by the endless belt project inward toward the center of the loop formed by the endless belt, wherein the drive unit is located at a point where portions of said loop are parallel to each other, wherein the axes of the sprocket wheels are mounted halfway between the parallel portions of the loop and wherein the sprocket wheels are of such a diameter that the rows of teeth on the sprocket wheel means straddle the teeth carried by said endless belt on both of said parallel portions of the loop, whereby the center strand of the drive chain engages the endless belt on both portions of the loop formed by the endless belt.

Claim 5

In a combination for driving a conveyor of the endless belt type, an endless belt, a plurality of teeth carried by the endless belt along a line parallel to the direction of movement of the endless belt, a drive unit comprising a drive coupling including two sprocket wheel means each having axially displaced rows of sprocket teeth and mounted for rotation about axes transverse to the path of the endless belt and longitudinally displaced from one another along the path of the endless belt, said sprocket wheel means being mounted with the teeth on the sprocket wheel means overlapping yet transversely displaced with respect to the teeth carried by said endless belt, a loop of multiple-strand driving chain having alternate strands of said loop being engaged by the teeth on the endless belt and the teeth on the sprocket wheel means, said teeth carried by the endless belt being provided with a negative pitch angle whereby the driving chain is drawn into and retained in engagement with the teeth carried by the endless belt over the range of travel between the sprocket wheel means thus eliminating the need for a slider bed, and motive means operative to impart rotational movement to one of said sprocket wheel means to drive said endless belt through said drive coupling whereby the necessity for means independent of the sprocket wheels to lift the driving chain into engagement with the teeth carried by the endless belt is eliminated.

Claim 6

In a combination for driving a conveyor of the endless belt type, an endless belt, a plurality of teeth carried by the endless belt along a line parallel to the direction of movement of the endless belt, a drive unit comprising a drive coupling including two sprocket wheel means each having axially displaced rows of sprocket teeth and mounted for rotation about axes transverse to the path of the endless belt and longitudinally displaced from one another along the path of the endless belt, said sprocket wheel means being mounted with the teeth on the sprocket wheel means overlapping yet transversely displaced with respect to the teeth carried by said endless belt, a loop of multiple-strand driving chain having alternate strands of said loop being engaged by the teeth on the endless belt and the teeth on the sprocket wheel means, said teeth carried by the endless belt being provided with a negative pitch angle whereby the driving chain is drawn into and retained in engagement with the teeth carried by the endless belt over the range of travel between the sprocket wheel means thus eliminating the need for a slider bed, and motive means operative to impart rotational movement to one of said sprocket wheel means to drive said endless belt through said drive coupling whereby the necessity for means independent of the sprocket wheels to lift the driving chain into engagement with the teeth carried by the endless belt is eliminated.

Claim 7

In a combination for driving a conveyor of the endless belt type, an endless belt forming a loop having parallel portions, a plurality of teeth carried by the endless belt along a line parallel to the direction of movement of the endless belt, said teeth projecting inwardly toward the center of the loop formed by the endless beLt, a drive unit comprising a drive coupling including two sprocket wheel means each having a pair of axially displaced rows of sprocket teeth and mounted for rotation about axes transverse to the path of the endless belt and longitudinally displaced from one another along the path of the endless belt, mounting means mounting said sprocket wheel means with the teeth on the sprocket wheel means overlapping yet transversely displaced with respect to the teeth carried by said endless belt, such that the teeth of each pair of rows straddle the teeth carried by the endless belt, said drive unit including a frame, a first mounting plate mounted on said frame and reciprocally slidable with respect to said frame in the direction of movement of the endless belt, a second mounting plate mounted on and carried by said first mounting plate and reciprocally movable with respect to said first mounting plate in the direction of movement of said endless belt, a first one of said sprocket wheel means being rotatably mounted to the first mounting plate and the second sprocket wheel means being rotatably mounted to the second mounting plate, said drive unit being located at a point where portions of the loop formed by the endless belt are parallel to each other, wherein the axes of the sprocket wheel means are mounted halfway between the parallel portions of said loop, said sprocket wheels being of such a diameter that the rows of teeth on the sprocket wheel means straddle the teeth carried by said endless belt on both of said parallel portions of the loop, whereby the center strand of the drive chain engages the endless belt on both portions of the loop formed by the endless belt, a loop of three strand driving chain having the side strands of said loop engaged by the corresponding row of sprocket teeth while the center strand engages the teeth carried by the endless belt, and motive means operative to impart rotational movement to one of said sprocket wheel means to drive said endless belt through said drive coupling whereby the necessity for means independent of the sprocket wheels to lift the driving chain into engagement with the teeth carried by the endless belt is eliminated.

Claim 8

In a combination for driving a conveyor of the endless belt type, an endless belt forming a loop having parallel portions, a plurality of teeth carried by the endless belt along a line parallel to the direction of movement of the endless belt, said teeth projecting inwardly toward the center of the loop formed by the endless beLt, a drive unit comprising a drive coupling including two sprocket wheel means each having a pair of axially displaced rows of sprocket teeth and mounted for rotation about axes transverse to the path of the endless belt and longitudinally displaced from one another along the path of the endless belt, mounting means mounting said sprocket wheel means with the teeth on the sprocket wheel means overlapping yet transversely displaced with respect to the teeth carried by said endless belt, such that the teeth of each pair of rows straddle the teeth carried by the endless belt, said drive unit including a frame, a first mounting plate mounted on said frame and reciprocally slidable with respect to said frame in the direction of movement of the endless belt, a second mounting plate mounted on and carried by said first mounting plate and reciprocally movable with respect to said first mounting plate in the direction of movement of said endless belt, a first one of said sprocket wheel means being rotatably mounted to the first mounting plate and the second sprocket wheel means being rotatably mounted to the second mounting plate, said drive unit being located at a point where portions of the loop formed by the endless belt are parallel to each other, wherein the axes of the sprocket wheel means are mounted halfway between the parallel portions of said loop, said sprocket wheels being of such a diameter that the rows of teeth on the sprocket wheel means straddle the teeth carried by said endless belt on both of said parallel portions of the loop, whereby the center strand of the drive chain engages the endless belt on both portions of the loop formed by the endless belt, a loop of three strand driving chain having the side strands of said loop engaged by the corresponding row of sprocket teeth while the center strand engages the teeth carried by the endless belt, and motive means operative to impart rotational movement to one of said sprocket wheel means to drive said endless belt through said drive coupling whereby the necessity for means independent of the sprocket wheels to lift the driving chain into engagement with the teeth carried by the endless belt is eliminated.

Claim 9

In a combination for driving a conveyor of the endless belt type, an endless belt, a plurality of teeth carried by the endless belt along a line parallel to the direction of movement of the endless belt, said teeth being arranged in two rows parallel to and equidistantly spaced on either side of the longitudinal axis of said endless belt, said teeth on the endless belt being provided with a negative pitch angle, a drive unit comprising a drive coupling for each of said rows of teeth carried by said endless belt, each drive coupling including two sprocket wheel means each having a pair of axially displaced rows of sprocket teeth, means mounting said sprocket wheel means for rotation about axes transverse to the path of the endless belt and longitudinally displaced from one another along the path of the endless belt, said sprocket wheel means being mounted with the teeth on the sprocket wheel means overlapping yet transversely displaced with respect to the teeth carried by said endless belt, such that the teeth of each pair of rows straddle the teeth carried by said endless belt, a loop of three strand driving chain having the center strand engaged by the teeth on the endless belt and the two side strands engaged by the teeth on the sprocket wheel means, and motive means operative to impart rotational movement to one of said sprocket wheel means in each drive coupling to drive said endless belt through said drive coupling whereby the necessity for means independent of the sprocket wheels to lift the driving chain into engagement with the teeth carried by the endless belt is eliminated.

Claim 10

In a combination for driving a conveyor of the endless belt type, an endless belt, a plurality of teeth carried by the endless belt along a line parallel to the direction of movement of the endless belt, said teeth being arranged in two rows parallel to and equidistantly spaced on either side of the longitudinal axis of said endless belt, said teeth on the endless belt being provided with a negative pitch angle, a drive unit comprising a drive coupling for each of said rows of teeth carried by said endless belt, each drive coupling including two sprocket wheel means each having a pair of axially displaced rows of sprocket teeth, means mounting said sprocket wheel means for rotation about axes transverse to the path of the endless belt and longitudinally displaced from one another along the path of the endless belt, said sprocket wheel means being mounted with the teeth on the sprocket wheel means overlapping yet transversely displaced with respect to the teeth carried by said endless belt, such that the teeth of each pair of rows straddle the teeth carried by said endless belt, a loop of three strand driving chain having the center strand engaged by the teeth on the endless belt and the two side strands engaged by the teeth on the sprocket wheel means, and motive means operative to impart rotational movement to one of said sprocket wheel means in each drive coupling to drive said endless belt through said drive coupling whereby the necessity for means independent of the sprocket wheels to lift the driving chain into engagement with the teeth carried by the endless belt is eliminated.

Claim 11

In a combination for driving a conveyor of the endless belt type, an endless belt forming a loop having parallel portions, a plurality of teeth carried by the endless belt along a line parallel to the direction of movement of the Endless belt, said teeth being arranged in two rows parallel to and equidistantly spaced on either side of the longitudinal axis of said endless belt, said teeth projecting inwardly toward the center of the loop, two drive units, each drive unit comprising a drive coupling for each of said rows of teeth carried by said endless belt, each drive coupling including two sprocket wheel means each having a pair of axially displaced rows of sprocket teeth and mounted for rotation about axes transverse to the path of the endless belt and longitudinally displaced from one another along the path of the endless belt, the corresponding sprocket wheel means on the two drive couplings being axially aligned with respect to each other, said sprocket wheel means being mounted with the teeth on the sprocket wheel means overlapping yet transversely displaced with respect to the teeth carried by said endless belt, such that the teeth of each pair of rows of the sprocket wheel means straddle the teeth carried by said endless belt, said drive unit being located at a point where portions of said loop are parallel to each other with one above the other, wherein the axes of the sprocket wheel means of both drive couplings are mounted halfway between the parallel portions of the loop and wherein said sprocket wheel means are of such a diameter that the rows of sprocket teeth straddle the teeth on the endless belt on both of the parallel portions of the endless belt, whereby the drive couplings engage the teeth on the endless belt on both the upper and lower runs on both sides, a loop of three strand driving chain having the center strand engaged by the teeth on the endless belt and the two side strands engaged by the teeth on the sprocket wheel means, and motive means mounted within the loop of the endless belt between the drive couplings, said motive means operative to impart rotational movement to one of said sprocket wheel means in each drive coupling to drive said endless belt through said drive coupling whereby the necessity for means independent of the sprocket wheels to lift the driving chain into engagement with the teeth carried by the endless belt is eliminated, said two drive units engaging and driving said endless belt on the top and bottom runs on both sides at two points, each of said drive units including a frame and a first pair of mounting plates mounted on either side of said frame and slidable with respect to said frame in the direction of movement of the endless belt, second mounting plates mounted on each of said first mounting plates and slidable with respect to the associated mounting plates in the direction of movement of the endless belt, first locking means for locking the first mounting plates in a selected position with respect to said frame, and second locking means for locking the second mounting plates in a selected position with respect to the first mounting plates, the driven sprocket wheel means in each drive coupling being rotatably mounted to the first mounting plate on the associated side of said frame and the undriven sprocket wheel means on each drive coupling being rotatably mounted to the corresponding second mounting plate whereby the drive couplings of one drive unit may be adjusted with respect to the corresponding drive couplings in the other drive unit by adjusting the positions of the first mounting plates of the one drive unit with respect to the associated frame so that the driving chains of both of the drive units can mesh with the teeth carried on the endless belt and whereby the slack in the drive chain in each drive coupling may be adjusted by adjusting the position of the associated second mounting plate with respect to the corresponding first mounting plate.

Claim 12

In a combination for driving a conveyor of the endless belt type, an endless belt forming a loop having parallel portions, a plurality of teeth carried by the endless belt along a line parallel to the direction of movement of the Endless belt, said teeth being arranged in two rows parallel to and equidistantly spaced on either side of the longitudinal axis of said endless belt, said teeth projecting inwardly toward the center of the loop, two drive units, each drive unit comprising a drive coupling for each of said rows of teeth carried by said endless belt, each drive coupling including two sprocket wheel means each having a pair of axially displaced rows of sprocket teeth and mounted for rotation about axes transverse to the path of the endless belt and longitudinally displaced from one another along the path of the endless belt, the corresponding sprocket wheel means on the two drive couplings being axially aligned with respect to each other, said sprocket wheel means being mounted with the teeth on the sprocket wheel means overlapping yet transversely displaced with respect to the teeth carried by said endless belt, such that the teeth of each pair of rows of the sprocket wheel means straddle the teeth carried by said endless belt, said drive unit being located at a point where portions of said loop are parallel to each other with one above the other, wherein the axes of the sprocket wheel means of both drive couplings are mounted halfway between the parallel portions of the loop and wherein said sprocket wheel means are of such a diameter that the rows of sprocket teeth straddle the teeth on the endless belt on both of the parallel portions of the endless belt, whereby the drive couplings engage the teeth on the endless belt on both the upper and lower runs on both sides, a loop of three strand driving chain having the center strand engaged by the teeth on the endless belt and the two side strands engaged by the teeth on the sprocket wheel means, and motive means mounted within the loop of the endless belt between the drive couplings, said motive means operative to impart rotational movement to one of said sprocket wheel means in each drive coupling to drive said endless belt through said drive coupling whereby the necessity for means independent of the sprocket wheels to lift the driving chain into engagement with the teeth carried by the endless belt is eliminated, said two drive units engaging and driving said endless belt on the top and bottom runs on both sides at two points, each of said drive units including a frame and a first pair of mounting plates mounted on either side of said frame and slidable with respect to said frame in the direction of movement of the endless belt, second mounting plates mounted on each of said first mounting plates and slidable with respect to the associated mounting plates in the direction of movement of the endless belt, first locking means for locking the first mounting plates in a selected position with respect to said frame, and second locking means for locking the second mounting plates in a selected position with respect to the first mounting plates, the driven sprocket wheel means in each drive coupling being rotatably mounted to the first mounting plate on the associated side of said frame and the undriven sprocket wheel means on each drive coupling being rotatably mounted to the corresponding second mounting plate whereby the drive couplings of one drive unit may be adjusted with respect to the corresponding drive couplings in the other drive unit by adjusting the positions of the first mounting plates of the one drive unit with respect to the associated frame so that the driving chains of both of the drive units can mesh with the teeth carried on the endless belt and whereby the slack in the drive chain in each drive coupling may be adjusted by adjusting the position of the associated second mounting plate with respect to the corresponding first mounting plate.

Claim 13

In a combination for driving a conveyor of the endless belt type, an endless belt forming a loop having parallel portions, a plurality of teeth carried by the endless belt along a line parallel to the direction of movement of the endless belt, said teeth being arranged in two rows parallel to and equIdistantly spaced on either side of the longitudinal axis of said endless belt, said teeth projecting inwardly toward the center of the loop, a drive unit comprising a drive coupling for each of said rows of teeth carried by said endless belt, each drive coupling including two sprocket wheel means each having a pair of axially displaced rows of sprocket teeth and mounted for rotation about axes transverse to the path of the endless belt and longitudinally displaced from one another along the path of the endless belt, the corresponding sprocket wheel means on the two drive couplings being axially aligned with respect to each other, said sprocket wheel means being mounted with the teeth on the sprocket wheel means overlapping yet transversely displaced with respect to the teeth carried by said endless belt, such that the teeth of each pair of rows of the sprocket wheel means straddle the teeth carried by said endless belt, said drive unit being located at a point where portions of said loop are parallel to each other with one above the other, wherein the axes of the sprocket wheel means of both drive couplings are mounted halfway between the parallel portions of the loop and wherein said sprocket wheel means are of such a diameter that the rows of sprocket teeth straddle the teeth on the endless belt on both of the parallel portions of the endless belt, whereby the drive couplings engage the teeth on the endless belt on both the upper and lower runs on both sides, a loop of three strand driving chain having the center strand engaged by the teeth on the endless belt and the two side strands engaged by the teeth on the sprocket wheel means, and motive means mounted within the loop of the endless belt between the drive couplings, said motive means operative to impart rotational movement to one of said sprocket wheel means in each drive coupling to drive said endless belt through said drive coupling whereby the necessity for means independent of the sprocket wheels to lift the driving chain into engagement with the teeth carried by the endless belt is eliminated, said motive means including a reducer, shafts for connecting said reducer to corresponding sprocket wheel means in the two drive couplings, and releasable connections in the shafts connecting said reducer to the selected sprocket wheels whereby said motive means can be removed by releasing the releasable connections without disturbing the drive couplings.

Claim 14

In a combination for driving a conveyor of the endless belt type, an endless belt forming a loop having parallel portions, a plurality of teeth carried by the endless belt along a line parallel to the direction of movement of the endless belt, said teeth being arranged in two rows parallel to and equIdistantly spaced on either side of the longitudinal axis of said endless belt, said teeth projecting inwardly toward the center of the loop, a drive unit comprising a drive coupling for each of said rows of teeth carried by said endless belt, each drive coupling including two sprocket wheel means each having a pair of axially displaced rows of sprocket teeth and mounted for rotation about axes transverse to the path of the endless belt and longitudinally displaced from one another along the path of the endless belt, the corresponding sprocket wheel means on the two drive couplings being axially aligned with respect to each other, said sprocket wheel means being mounted with the teeth on the sprocket wheel means overlapping yet transversely displaced with respect to the teeth carried by said endless belt, such that the teeth of each pair of rows of the sprocket wheel means straddle the teeth carried by said endless belt, said drive unit being located at a point where portions of said loop are parallel to each other with one above the other, wherein the axes of the sprocket wheel means of both drive couplings are mounted halfway between the parallel portions of the loop and wherein said sprocket wheel means are of such a diameter that the rows of sprocket teeth straddle the teeth on the endless belt on both of the parallel portions of the endless belt, whereby the drive couplings engage the teeth on the endless belt on both the upper and lower runs on both sides, a loop of three strand driving chain having the center strand engaged by the teeth on the endless belt and the two side strands engaged by the teeth on the sprocket wheel means, and motive means mounted within the loop of the endless belt between the drive couplings, said motive means operative to impart rotational movement to one of said sprocket wheel means in each drive coupling to drive said endless belt through said drive coupling whereby the necessity for means independent of the sprocket wheels to lift the driving chain into engagement with the teeth carried by the endless belt is eliminated, said motive means including a reducer, shafts for connecting said reducer to corresponding sprocket wheel means in the two drive couplings, and releasable connections in the shafts connecting said reducer to the selected sprocket wheels whereby said motive means can be removed by releasing the releasable connections without disturbing the drive couplings.

Claim 15

The combination of claim 8 wherein said shafts connecting the reducer to the sprocket wheel means each comprise two axially aligned shafts and wherein the releasable connections include a radial flange fixedly connected to the end of one shaft, a second radial flange slidably fitted on the end of said second shaft, said second radial flange having a collar with an axially aligned slot therethrough and an aperture transverse to the axis of a shaft through the slotted portions of said collar, adjustable fasteners inserted in said aperture and operative to apply a clamping force to said slotted collar to cause it to rigidly grip the second shaft and axially aligned adjustable fasteners operative to clamp the two flanges to the associated sprocket wheels in the drive couplings.

Claim 16

In a combination for driving a conveyor of the endless belt type, an endless belt, a plurality of teeth carried by the endless belt along a line parallel to the direction of movement of the endless belt, said teeth being arranged in two rows parallel to and equidistantly spaced on either side of the longitudinal axis of said endless belt, a drive unit comprising a drive coupling for each of said rows of teeth carried by said endless belt, each drive coupling including two sprocket wheel means each having a pair of axially displaced rows of sprocket teeth and mounted for rotation about axes transverse to the path of the endless belt and longitudinally displaced from one another along the path of the endless belt, said sprocket wheel means being mounted with the teeth on the sprocket wheel means overlapping yet transversely displaced with respect to the teeth carried by said endless belt, such that the teeth of each pair or rows of the sprocket wheel means straddle the teeth carried by said endless belt, a loop of three strand driving chain having the center strand engaged by the teeth on the endless belt and the two side strands engaged by the teeth on the sprocket wheel means, motive means operative to impart rotational movement to one of said sprocket wheel means in each drive coupling to drive said endless belt through said drive coupling whereby the necessity for means independent of the sprocket wheels to lift the driving chain into engagement with the teeth carried by the endless belt is eliminated, handrails in the form of additional endless belts one on either side of said endless belt, said handrails having an upper run which serves as a support for passengers on the endless belt and a return run adjacent said endless belt, and roller drive means on either side of said endless belt for engaging and driving the associated handrail and coupling means for coupling the roller drive means on each side of the endless belt to the driven sprocket wheel means in the corresponding drive coupling.

Claim 17

In a combination for driving a conveyor of the endless belt type, an endless belt, a plurality of teeth carried by the endless belt along a line parallel to the direction of movement of the endless belt, said teeth being arranged in two rows parallel to and equidistantly spaced on either side of the longitudinal axis of said endless belt, a drive unit comprising a drive coupling for each of said rows of teeth carried by said endless belt, each drive coupling including two sprocket wheel means each having a pair of axially displaced rows of sprocket teeth and mounted for rotation about axes transverse to the path of the endless belt and longitudinally displaced from one another along the path of the endless belt, said sprocket wheel means being mounted with the teeth on the sprocket wheel means overlapping yet transversely displaced with respect to the teeth carried by said endless belt, such that the teeth of each pair or rows of the sprocket wheel means straddle the teeth carried by said endless belt, a loop of three strand driving chain having the center strand engaged by the teeth on the endless belt and the two side strands engaged by the teeth on the sprocket wheel means, motive means operative to impart rotational movement to one of said sprocket wheel means in each drive coupling to drive said endless belt through said drive coupling whereby the necessity for means independent of the sprocket wheels to lift the driving chain into engagement with the teeth carried by the endless belt is eliminated, handrails in the form of additional endless belts one on either side of said endless belt, said handrails having an upper run which serves as a support for passengers on the endless belt and a return run adjacent said endless belt, and roller drive means on either side of said endless belt for engaging and driving the associated handrail and coupling means for coupling the roller drive means on each side of the endless belt to the driven sprocket wheel means in the corresponding drive coupling.

Claim 18

In a combination for driving a conveyor of the endless belt type, an endless belt, a plurality of teeth carried by the endless belt along a line parallel to the direction of movement of the endless belt and a drive unit comprising a drive coupling including two sprocket wheel means each having a pair of axially displaced rows of sprocket teeth and mounted for rotation about axes transverse to the path of the endless belt and longitudinally displaced from one another along the path of the endless belt, said sprocket wheel means being mounted with the teeth on the sprocket wheel means overlapping yet transversely displaced with respect to the teeth carried by said endless belt, such that the teeth of each pair of rows straddle the teeth carried by the endless belt, a loop of three strand driving chain having the center strand engaged by the teeth on the endless belt and the two side strands engaged by the teeth on the sprocket wheel means, said center strand of the three strand drive chain having a pitch which differs from that of said side strands, and motive means operative to impart rotational movement to one of said sprocket wheel means to drive said endless belt through said drive coupling whereby the necessity for means independent of the sprocket wheels to lift the driving chain into engagement with the teeth carried by the endless belt is eliminated.

Claim 19

In a combination for driving a conveyor of the endless belt type, an endless belt, a plurality of teeth carried by the endless belt along a line parallel to the direction of movement of the endless belt and a drive unit comprising a drive coupling including two sprocket wheel means each having a pair of axially displaced rows of sprocket teeth and mounted for rotation about axes transverse to the path of the endless belt and longitudinally displaced from one another along the path of the endless belt, said sprocket wheel means being mounted with the teeth on the sprocket wheel means overlapping yet transversely displaced with respect to the teeth carried by said endless belt, such that the teeth of each pair of rows straddle the teeth carried by the endless belt, a loop of three strand driving chain having the center strand engaged by the teeth on the endless belt and the two side strands engaged by the teeth on the sprocket wheel means, said center strand of the three strand drive chain having a pitch which differs from that of said side strands, and motive means operative to impart rotational movement to one of said sprocket wheel means to drive said endless belt through said drive coupling whereby the necessity for means independent of the sprocket wheels to lift the driving chain into engagement with the teeth carried by the endless belt is eliminated.

Claim 20

The combination of claim 11, wherein the pitch of the center strand of the drive chain is twice the pitch of the side strands, wherein the pitch of the teeth on said endless belt is substantially the same as the pitch of the center strand of the drive chain and wherein the center strand of the drive chain is provided with rollers of resilient material whereby the center strand will accommodate to distribute the driving force over a plurality of teeth on the endless belt.

Claim 21

The combination of claim 12, wherein the teeth carried by the endless belt are provided with a negative pitch angle.

Claim 22

In a combination for driving a conveyor of the endless belt type, an endless belt, a plurality of teeth carried by the endless belt along a line parallel to the direction of movement of the endless belt and a drive unit comprising a drive coupling including two sprocket wheel means each having a pair of axially displaced rows of sprocket teeth and mounted for rotation about axes transverse to the path of the endless belt and longitudinally displaced from one another along the path of the endless belt, said sprocket wheel means being mounted with the teeth on the sprocket wheel means overlapping yet transversely displaced with respect to the teeth carried by said endless belt, such that the teeth of each pair of rows straddle the teeth carried by the endless belt, said sprocket wheel means each including a drum having two axially displaced roWs of sprocket teeth extending radially from the periphery thereof, a loop of three strand driving chain having the center strand engaged by the teeth on the endless belt and the two side strands engaged by the teeth on the sprocket wheel means, the pitch of the center strand of the drive chain and the teeth on said endless belt being twice the pitch of the sprocket teeth and the side strands of the driving chain, said driving chain including rollers in each strand with the rollers of the center strand being resilient rollers having a diameter substantially larger than the rollers on the side strands of the drive chain, said drum having an annular groove in its periphery between the rows of sprocket teeth, said groove being adequate to accommodate the larger diameter rollers on the center strand of the driving chain, and motive means operative to impart rotational movement to one of said sprocket wheel means to drive said endless belt through said drive coupling whereby the necessity for means independent of the sprocket wheels to lift the driving chain into engagement with the teeth carried by the endless belt is eliminated.

Claim 23

In a combination for driving a conveyor of the endless belt type, an endless belt, a plurality of teeth carried by the endless belt along a line parallel to the direction of movement of the endless belt and a drive unit comprising a drive coupling including two sprocket wheel means each having a pair of axially displaced rows of sprocket teeth and mounted for rotation about axes transverse to the path of the endless belt and longitudinally displaced from one another along the path of the endless belt, said sprocket wheel means being mounted with the teeth on the sprocket wheel means overlapping yet transversely displaced with respect to the teeth carried by said endless belt, such that the teeth of each pair of rows straddle the teeth carried by the endless belt, said sprocket wheel means each including a drum having two axially displaced roWs of sprocket teeth extending radially from the periphery thereof, a loop of three strand driving chain having the center strand engaged by the teeth on the endless belt and the two side strands engaged by the teeth on the sprocket wheel means, the pitch of the center strand of the drive chain and the teeth on said endless belt being twice the pitch of the sprocket teeth and the side strands of the driving chain, said driving chain including rollers in each strand with the rollers of the center strand being resilient rollers having a diameter substantially larger than the rollers on the side strands of the drive chain, said drum having an annular groove in its periphery between the rows of sprocket teeth, said groove being adequate to accommodate the larger diameter rollers on the center strand of the driving chain, and motive means operative to impart rotational movement to one of said sprocket wheel means to drive said endless belt through said drive coupling whereby the necessity for means independent of the sprocket wheels to lift the driving chain into engagement with the teeth carried by the endless belt is eliminated.

Claim 24

The combination of claim 14 wherein the dedendum of the teeth carried by the endless belt is undercut to provide a negative pitch angle on said teeth.

Claim 25

The combination of claim 15 wherein the negative pitch angle is on the order of 5* .

Claim 26

In combination, an endless belt, a row of teeth carried by the endless belt along a line parallel to the direction of movement of the endless belt, and a plurality of drive units engaging said row of teeth carried by said endless belt at a plurality of points for driving said endless belt in its endless path, each of said drive units comprising a frame, a first mounting plate mounted on said frame and reciprocally slidable with respect to said frame in the direction of movement of the endless belt, a second mounting plate mounted on and carried by the first mounting plate and reciprocally movable with respect to said first mounting plate in the direction of movement of said endless belt, first locking means for locking said first mounting plate in a selected position with respect to said frame, second locking means for locking in the second locking mounting plate in a selected position with respect to said first mounting plate, a first sprocket wheel rotatably mounted on and carried by said first mounting plate, a second sprocket wheel rotatably mounted on and carried by said second mounting plate, and a drive chain supported and driven in a loop by said first and second sprocket wheels with a portion of said loop in engagement with the teeth carried by said endless belt whereby the drive chain of one drive unit may be adjusted with respect to the drive chain in another drive unit by adjusting the position of the first mounting plate of the one drive unit with respect to the corresponding frame so that the driving chains of both of the drive units can mesh with the teeth carried on the endless belt and whereby the slack in the drive chain in each drive unit may be adjusted by adjusting the position of the associated second mounting plate with respect to the corresponding first mounting plate.

Claim 27

In combination, an endless belt, a row of teeth carried by the endless belt along a line parallel to the direction of movement of the endless belt, and a plurality of drive units engaging said row of teeth carried by said endless belt at a plurality of points for driving said endless belt in its endless path, each of said drive units comprising a frame, a first mounting plate mounted on said frame and reciprocally slidable with respect to said frame in the direction of movement of the endless belt, a second mounting plate mounted on and carried by the first mounting plate and reciprocally movable with respect to said first mounting plate in the direction of movement of said endless belt, first locking means for locking said first mounting plate in a selected position with respect to said frame, second locking means for locking in the second locking mounting plate in a selected position with respect to said first mounting plate, a first sprocket wheel rotatably mounted on and carried by said first mounting plate, a second sprocket wheel rotatably mounted on and carried by said second mounting plate, and a drive chain supported and driven in a loop by said first and second sprocket wheels with a portion of said loop in engagement with the teeth carried by said endless belt whereby the drive chain of one drive unit may be adjusted with respect to the drive chain in another drive unit by adjusting the position of the first mounting plate of the one drive unit with respect to the corresponding frame so that the driving chains of both of the drive units can mesh with the teeth carried on the endless belt and whereby the slack in the drive chain in each drive unit may be adjusted by adjusting the position of the associated second mounting plate with respect to the corresponding first mounting plate.

Claim 28

The combination of claim 17, wherein said endless belt is arranged with an upper load bearing run and a lower return run with portions of said runs parallel to each other and wherein portions of said loops in said drive chains engage the teeth carried by said endless belt in both the load bearing and return runs.

Claim 29

The combination of claim 17, including a second row of teeth carried by the endless belt along a line parallel to the direction of movement of said endless belt, said rows of teeth being equidistantly spaced on either side of the longitudinal axis of said endless belt, a pair of said first mounting plates mounted one on either side of said frame and reciprocally slidable with respect to said frame in the direction of movement of the endless belt, a pair of said second mounting plates Mounted one on each of said first mounting plates and reciprocally slidable with respect to the corresponding first mounting plate in a direction of movement of said endless belt, first locking means for locking each of said first mounting plates in a selected position with respect to said frame, second locking means for locking each of said second mounting plates in a selected position with respect to the corresponding first mounting plate, a pair of first sprocket wheels one rotatably mounted on and carried by each of said first mounting plates, a pair of second sprocket wheels one rotatably mounted on and carried by each of said second mounting plates, and a pair of drive chains each one supported and driven in a loop by one of said first and second sprocket wheels with a portion of each of said loops in engagement with one of said rows of teeth carried by the endless belt.