US3712454A

US3712454A - Powered roller mechanism

Info

Publication number: US3712454A
Application number: US00117125A
Authority: US
Inventors: J Mckee
Original assignee: REPUBLIC NAT BANK OF DALLAS
Current assignee: HTL INDUSTRIES Inc A CORP OF; REPUBLIC NAT BANK OF DALLAS
Priority date: 1971-02-19
Filing date: 1971-02-19
Publication date: 1973-01-23
Anticipated expiration: 1990-01-23

Abstract

A powered roller movable laterally of its axis between a retracted position and an advanced position is unitary with the ring gear of an eccentric planetary gear set having a sun gear input. The ring gear is journalled on the planet gear carrier eccentrically thereof for movement thereby along an orbit between the two positions of the roller.

Description

nited States Patent 1191 McKee Jan. 23, 1973 POWERED ROLLER MECHANISM [75] Inventor: James E. McKee, Goleta, Calif.

[73] Assignees: Republic National Bank of Dallas;

Irving Trust Company; Union Bank [22] Filed: Feb. 19, 1971 21 Appl.No.: 117,125

Related U.S. Application Data [63] Continuation of Ser. No. 865,071, Oct. 9, i969,

abandoned.

[52] U.S. Cl. ..l98/127 R [51] Int. Cl. ..B65g 13/02 [58] Field of Search ..l98/l27; 214/84; 244/137 [56] References Cited UNITED STATES PATENTS 3,447,665 6/1969 Egeland ..2i4/84 X 3,568,821 3/1971 Gronkuist ..l98/127 R Primary ExaminerEdward A. Sroka Attorney-Smyth, Roston & Pavitt [5 7} ABSTRACT A powered roller movable laterally of its axis between a retracted position and an advanced position is unitary with the ring gear of an eccentric planetary gear set having a sun gear input. The ring gear is journalled on the planet gear carrier eccentrically thereof for movement thereby along an orbit between the two positions of the roller.

23 Claims, 16 Drawing Figures PATENTEI] M2 7 3,712,454

SHEET 10F 5 Gin/145$ MCSKEE PAIENTEDJAHZEI I973 I 3,712,454

SHEET 5 BF 5 OOGOOOOO 52 o o o o 0 7? fire/J2.

JM Eyme.

POWERED ROLLER MECHANISM This application is a continuation of U.S. application Ser. No. 865,071, filed Oct. 9, 1969 and now abandoned.

BACKGROUND OF THE INVENTION For a number of widely different purposes it is useful to rotate a rotary body and to shift the rotary body on a path transversely of its axis from a retracted position to one or more advanced positions. For example, the rotary body may be a grinding wheel which is advanced towards a workpiece that is to be processed.

The invention has special utility in the form of a powered roller that is normally retracted below a support plane and, when desired, is advanced upward for tangential contact with the bottom surfaces of objects to move the objects along the support plane. The initial embodiment of the invention is employed in this manner to shift heavy cargo items along the cargo space of a vehicle such as a jet aircraft. The description herein of this initial embodiment will provide adequate guidance for persons skilled in the art who may have occasion to apply the underlying concept of the invention to other specific purposes.

The cargo space of an airplane is commonly provided with built-in freely rotatable support elements in the form of balls and rollers which define a support plane for palletized or containerized cargo items and which minimize frictional resistance to movement of the cargo items along the support plane. For the purpose'of illustration, the invention will be described as applied to such a builtin structure of the character disclosed in the Davidson U.S. Pat. No. 3,262,588 issued July 26, 1966, whichprior disclosure is hereby incorporated into the present disclosure by reference.

in the Davidson disclosure, the floor of the cargo space that is opposite the side door of the aircraft is provided with a ball mat, the universally rotatable balls of which define a support plane and serve to minimize frictional resistance to movement of cargo items from the doorway onto the door mat as well as to minimize frictional resistance to direction change of the cargo items and initial movement of the cargo items longitudinally of the aircraft. The areas of the floor space that extend in both longitudinal directions from the ball mat are provided with rotatable support elements in the form of rollers having their axis perpendicular to the longitudinal axis of the aircraft, the rollers being mounted on so-called trays that are releasably anchored to seat rails in longitudinal alignment with the aircraft.

The described arrangement of ball mats and roller trays greatly facilitates stowing cargo units in the aircraft but nevertheless physical effort and appreciabletime is required to push a cargo item from the region of the side door to thecentral area of the ball mat and then to transfer the cargo unit to the roller trays for movement longitudinally of the aircraft. Usually at least five men are required to load or unload av large: cargo aircraft in 30 to -40 minutes and, based on an average load per aircraft today of 58,000 pounds, only 11 planes a day can be loaded or unloaded by acargohandling crew. It is also to be noted that serious hazards to the cargo handlers are involved in such a manual operation.

With the era approaching of jet aircraft such as the Boeing 747 and the Lockheed L-l0ll of greatly increased cargo capacity and correspondingly increased fixed costs, concerted efforts are now being made to meet the need for more nearly automated cargo handling methods involving powered means incorporated in the structure of the cargo space to move cargo items under more or less remote control. A primary object of the present invention is to meet the various problems involved in satisfying this need and thus make it possible for one man, or at most two men, to load 100,000 pounds of cargo or more into a large aircraft in 20 minutes or less.

It has been determined that the new requirements may be met by providing the cargo space of the aircraft with suitably constructed reversible powered rollers to cooperate both with the universally rotatable balls of the ball mats and with the rollers of the longitudinal roller trays, provided that the powered rollers are shiftable by remote control from retracted positions out of the way below the support plane of the cargo space'to upper positions at which the powered rollers protrude above the support plane for tangential traction contact with the bottom surfaces of the cargo items.

For example, a pair of reversible retractable power rollers with their axis parallel with the aircraft axis may propel cargo items from the region of the side door a desired distance across the ball mat where a powered roller with its axis perpendicular to the longitudinal axis of the aircraft may take over to initiate movement of the cargo items in either direction longitudinally of the aircraft away from the entrance area. A third powered roller of the same orientation. as the second powered roller may complete the longitudinal travel of cargo items from the ball mat into the short bay forward of theside'door and successive similarly oriented powered rollers may successively engage cargo items to propel the items longitudinally of the aircraft any required distance towards the rear end of the cargo space.

The specific objects of the presently preferred embodiment of the invention include the following: to provide a reversible powered roller unit that is compact enough to fitinto the shallow space between the cargo support plane and the floor of the aircraft and yet is powerful enough to propel a cargo item weighing up to 13,500 or more pounds at a rate, for example of feet per minute; to make such a powered roller unit substantially immune to impact damage by portions of cargo items that. may sag below the support plane; to provide sufficient power to move the heaviest cargo itern-andat the. same time safeguard the powered roller mechanism from damaging stress in the event that movement of .the cargo item is abruptly blocked while therolleris energized; to provide efficient means to raiseand lower the powered roller under remote control with minimal addition of structure required to raise and, lower the roller and without complicating theremote control, only one signal being requiredboth to cause energization and raising of the roller or to cause mediately adjacent a cargo item when a powered roller is energized to propel the cargo item.

3 SUMMARY OF THE INVENTION As will be explained more fully, the invention takes advantage of the unique and highly advantageous geometrical behavior of what may be termed an eccentric planetary gear train comprising: an input sun gear; a planet gear carrier with its axis of rotation concentric to the sun gear; a ring gear mounted on the carrier ec-' centrically thereof, i.e., with its axis of rotation offset from the common axis of rotation of the carrier and sun gear; and a planet gear journalled on the carrier in mesh with both the sun gear and the ring gear. Such a planetary gear train may be adapted to the purpose of the present invention by simply making the cargo- .propelling roller unitary with the ring gear. Preferably the ring gear is a cylindrical member of substantially approximately the same axial dimension as the propelling roller with the propelling roller encasing the ring gear and with the carrier axially elongated to extend beyond both ends of the cylindrical ring gear for effective support of the propelling roller.

A basic advantage of such an arrangement is that rotation of the planet gear carrier moves the propelling roller in an orbit between a retracted position below the cargo support plane and an upper position protruding sufficiently above the support plane for effective traction contact against the bottom surface of a cargo unit. With the planet gear cooperative with the sun gear effective to reversibly rotate the propelling roller on its axis at any orbital position of the propelling roller, the only further actuation requirements are rotation of the carrier to raise and lower the propelling roller and when the propelling roller reaches its upper position. In

the present embodiment of the invention both latches are carried, by a reciprocative yoke which is spring biased in one direction and is operable by solenoid means in the opposite direction.

releasable immobilization of the carrier at the elevated position of the propelling roller.

Within the scope of the invention various means may be provided to rotate and releasably immobilize the carrier. For example a second power input in addition to the sun gear may be provided to rotate the carrier directly under remote control. A feature of the preferred practice of the invention, however, is the concept of using the sun gear as the sole power input and of diverting at least a portion of the power flow temporarily to rotate the carrier when required for raising and lowering the propelling roller. In this regard an important feature of the present embodiment of the invention is the further concept of frictionally coupling the planet gear carrier and the ring gear to provide the required diversion of the power flow.

The friction coupling causes rotation of the planet gear carrier whenever energization of the sun gear is initiated in either rotary direction and the invention provides a first latch to immobilize the carrier automatically when the cargo-propelling roller rises to its effective upper position. Subsequent deenergization of the latch to unlatch the carrier to permit the sun gear to rotate the carrier to lower the cargo-propelling roller to its retracted position whereupon a second latch automatically immobilizes the carrier to keep the roller retracted.

In the preferred embodiment of the invention this automatic dual latch concept is carried out by forming the carrier with a surface concentric to its axis of rotation with a suitable latch recess therein that is engaged by the first latch when the propelling roller is elevated and is engaged by the second latch when rotation of the carrier retracts the propeller roller. With the first latch spring biased away from the carrier and the Other features of the invention include: the incorporation of a motor in the powered roller unit to energize the sun gear; the further incorporation of reduction gearing of the planetary type; the combination with the planetary reduction gearing of torque limiter means; the provision of a switch mechanically operated by a solenoid-actuated latch for the planet gear carrier, which switch energizes the motor whenever the latch releases the carrier at the lower retracted position of the cargo-propelling roller; the provision of a control.

switch with a push button to energize the latch solenoid as long as the push button is depressed with the further provision of delay means to prolong the energization of the motor for a predetennined number of seconds after the push button is released; the provision of simple friction means to couple the carrier and ring gear; and the shaping ,of the housing of the powered roller item with inclined marginal surfaces to minimize input damage to the item by sagging portions of cargo items.

The various features and advantages of the invention may be understood by reference to the following detailed description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, which are to be regarded as merely illustrative: I

FIG. 1 is a diagrammatic view to explain the geometrical behavior of what may be termed an eccentric planetary gear train that is a basic feature of the invention;

FIG. 2 is a diagram showing a cargo-propelling roller encasing the ring gear and showing two latches controlled by a solenoid and a cooperating spring, the mechanism being shown at the normal lower position of the cargo-propelling roller with the solenoid deenergized;

FIG. 3 is a view similar to FIG. 2 with the powered roller atits upper position to propel a cargo item, the solenoid being energized;

FIG. 4 is a view similar to FIG. 3 showing the solenoid deenergized to permit the cargo-propelling roller to return to its normal lower position;

FIG. 4a is a diagrammatic view of a modification wherein retarding means acting externally on the roller causes the roller to be elevated when the sun gear is energized;

FIG. 5 is a plan view of the presently preferred embodiment of the invention with parts broken away;

FIG. 6 is a longitudinal sectional view of a longitudinal portion of the structure shown in FIG. 5;

FIG. 7 is a longitudinal sectional view on a different plane showing the rest of the structure;

FIG. 8 is a plan view of the latch yoke;

FIG. 9 is a side elevational view of the yoke;

FIG. 10 is an end elevation on reduced scale of the structure shown in FIG. 5;

FIG. 10a is a fragmentary view in side elevation of an alternate form of a torque limiter that may be employed;

FIG. 11 is a fragmentary diagrammatic plan view of the cargo space of an aircraft;

FIG. 12 is a wiring diagram of a control circuit for a propeller roller unit;

FIG. 13 is a diagrammatic side elevational view illustrating how the principles of the invention may be embodied in means to drive and shift a grinding wheel; and

FIG. 14 is a view taken along the line 14-14 of FIG. 13 showing means to indicate the advance of the grinding wheel.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION BASIC MODE OF OPERATION FIG. 1 shows what may be termed an eccentric planetary gear train that is a basic feature of the invention. The gear train includes an input sun gear 20, a planet gear carrier 22 with its axis of rotation concentric to the sun gear, a ring gear 24 and a planet gear 25 that is in mesh both with the sun gear and the ring gear. The planetary gear train is eccentric in the-sense that the ring gear 24 is journalled on the planet gear carrier 22 for rotation on an eccentric axis 26, the axis 26 being offset from the common axis of rotation 28 of the sun gear and planet gear carrier. It is apparent that rotation of the carrier 22 on the axis 28 moves the axis 26 of the ring gear in a circular orbit. In FIG. 1 the ring gear is at the top of its'orbit with its axis 26 at the point designated 26. When the ring gear is at its opposite position at the bottom of its orbit its axis is at the point designated 30 in FIG. 1.

If the carrier 22 is immobilized by any given orbital position of the ring gear 24, power flows from the input. sun gear through the planet gear 25 to the ring gear to Thus power from the sun gear 20 may flow to the ring gear alone to cause rotation of the ring gear at whatever degree of elevation the ring gear may be or the power flow may be diverted to the carrier 22 whenever it is desired to change the elevation of the ring gear. his to be understood, however, that within the-scope of the invention instead of diverting power flow from the sun gear to the carrier '22 to raise and lower the ring'geana second power input may be applied directly to the carrier to raise and lower the ring gear.

FIG. 2 shows how the underlying concept of aneccentric planetary. gear train is incorporated in the presently preferred embodiment of the invention. In the construction represented by FIG. 2, the ring gear 24 is an elongated cylinder and a cargo-moving roller, generally designated 32, is in the form of a cylinder that fixedly encases the ringgear cylinder. The roller may be equipped with a suitable coating 34 of plastic, for example polyurethane, for frictional contact with the cargo. The carrier 22 is of circular peripheral configuration with a single latch recess 35 for cooperation alternately with a first latch 36 and a second latch 38, the two latches being unitary parts of a reciprocative yoke 40. In FIG. 2 the roller 32 is in its normal position at the bottom of its orbit and the yoke 40 is in its normal position biased to the right by a spring 42 to bias the first latch 36 away from the carrier 22 and to holdthe second latch 36 in engagement with the latch recess 35 to immobilize the carrier but the bias of the yoke may be reversed by a solenoid 44.

In the preferred embodiment of the invention, rotation of the carrier 22 to raise and lower the roller 32 is accomplished by frictionally coupling two components of the planetary gearing. For this purpose the double arrow 45 in FIGS. 2-4 represents frictional means effective between the ring gear 24 and the carrier 22 to yieldingly lock up the planetary gear train for rotation as a unit, the friction means acting specifically between the roller 32 and the carrier.

In the preferred practice of the invention the solenoid 44 is energized in time relation to energization of the motor that drives the sun gear 20 and for this purpose, the motor is controlledby a switch 46 shown in FIGS. 2-4 which is responsive to the shifting of the latch yoke 40. The switch 46 is normally closed and is in its normally closed state in FIG. 2. The latch yoke 40 is shown in solid lines at its right limit position in FIG. 2 and the dotted lines in FIG. 2 indicate an intermediate position of the switch at which the latch 36 presses against the periphery of the carrier 22, the latch recess 35 being remote from the latch 36. FIG. 4 shows the latch yoke at another intermediate position at which the solenoid 44 is deenergized and the spring 42 urges the latch 38 against the arcuate periphery of the carrier 22. FIG. 3 shows the roller 32 at its upper position with the latch yoke at its left limit position. The switch 46 that controls the motor is normally open and is open in FIG. 2, where the latch yoke is at its right limit position. Atall other positions of the latch yoke, including the intermediate position indicated by dotted lines in FIG. 2 and the intermediate position shown in FIG. 4,.the switch 46 is closed to energize the motor. Thus the switch 46 is closed at all positions of the latch yoke 40 except the right limit position shown in FIG. 2.

The operating cycle is as follows: Starting with the parts intheir normal positions shown in FIG. 2, the motor and the solenoid being deenergized and the cargo-propelling roller 32 being at its normal lower retracted position, the latch 38 is in engagement with the latch recess 35 to immobilize the carrier 22 and the latch 36 is retracted. When the solenoid 44 is energized by a control signal the latch yoke 40 is shifted leftward from itsnormal position to an intermediate position indicated by dotted-lines in FIG. 2 where the latch 36 presses against the arcuate periphery of the carrier 22. This initial leftward shift of the latch yoke 40 closes the switch 46 to actuate the sun gear 20, whereupon the carrier 22 rotates 180 by virtue .of the frictional coupling of the carrier and the ring gear. With the solenoid'pulling the latch 36 against the periphery of the carrier 22, the latch 36 snaps into engagement with the latch recess 35-at theend of the 180 of rotation of the carrier to immobilize the carrier as shown in FIG. 3 withthe cargo-propelling roller 32 at its elevated position. In effect, the frictional coupling between the ring gear and the carrier locks up the planetary gear train to carry out the l of rotation of the carrier.

When the control signal is subsequently removed with the parts in the positions shown in FIG. 3, the latch yoke 40 is shifted rightward by the spring 42 to cause the latch 36 to release the carrier 22 and to cause the latch 38 to press against the periphery of the carrier as shown in FIG. 4. Switch 46 remains closed for continued energization of the motor until another 180 of rotation of the carrier 22 is completed to permit the latch 38 to seat again in the latch recess to immobilize the carrier 22 with the cargo-propelling roller at its normal retracted position. The final shift of the latch yoke 40 rightward from the position shown in FIG. 4 to the normal position shown in FIG. 2 opens the switch 46 to deenergize the motor with the cargo-propelling roller 32 at its lower retracted position.

If the ring gear 24 with the roller 32 fixedly mounted thereon is held against rotation while the sun gear 20 is energized, the carrier 22 will rotate to move the nonrotating roller in a rotary path. It is apparent, therefore, that instead of frictionally coupling the carrier and the ring gear to change the elevation of the roller 32, simple frictional brake means may be applied directly to the roller.

FIG. 4a shows how such a brake means in the form of a leaf spring 47 may be mounted below the roller 32 to exert upward pressure against the underside of the roller when the roller is atits lower retracted position. The range of resilient flexure of the leaf spring 46 is sufficient to follow the upward movement of the. roller from its retracted position until the roller makes initial frictional contact with a cargo item whereupon the cargo item takes over the function of retarding the roller. The roller 32 then completes its upward movement to its upper limit position to lift the cargo item and, preferably, in doing so moves out of the range of the leaf spring. If desired, an equivalent of the leaf spring may be employed in the form of a resilient-body of elastomeric material, such as a suitable foamed plastic.

STRUCTURAL DETAILS OF THE PREFERRED EMBODIMENT Turning now to the specific structure of the presently preferred embodiment of the invention and referring first to FIGS. 6 and 7, a motor, generally designated 50, has a shaft 52 which is journalled in bearings 54 and, by means which will be described later, the shaft is operatively connected to a first spur gear 55 near the right end of FIG. 6. The first spur gear 55 in turn meshes with a second spur gear 56 shown near the left end of FIG. 7 which is keyed to a shaft 58 that is journalled in bearings 60. The shaft 58 carries an axially elongated previously mentioned sun gear 20 inside the cargopropelling roller 32.

Rotatably mounted on the sun gear shaft 58 by bearings 62 is the previously mentioned planet gear carrier 22 which is axially elongated and carries a pair of coaxial planet gears which comprise the previously mentioned planet gear 25. The planet gears 25 are mounted by bearings as shown in individual stub shafts 64. The planet gear carrier 22 has an eccentric outer peripheral surface of cylindrical cross section on which the previously mentioned ring gear 24 is mounted by bearings 64, the ring gear being of the configuration of an axially elongated cylinder. Thus the ring gear 24 rotates on an axis that is offset from the common axis of corresponding O-rings 68 in peripheral contact with the carrier 22.

For the purpose of frictionally coupling the ring gear 24 and the carrier 22, a collar 70 mounted on the carrier and secured thereto by a radial screw 72 cooperates with a circumferential wafer spring 74 of undulating configuration which is confined under light stress between the collar 70 and the previously mentioned intemal ring 65 of the cargo-propelling roller 32. Thus the wafer spring is effective to lock up the planetary gear train in a yielding manner to cause orbital movement of the cargo propelling roller 32.

In the construction shown, the motor 50 and associated components for actuating the sun gear 20 are enclosed in a low profile housing 75 with the sun gear and the carrier extending beyond one end of the housing as shown in FIGS. 5 and 7. As best shown in FIG. 5, a unitary part of the housing 75 is a guard 76 that extends around the opposite sides and outer end of the cargo-propelling roller 32, the purpose of the guard being to protect the roller and especially so at the lower retracted position of the roller. The guard 76 also serves to support outer bearing 60 of the sun gear shaft As shown in FIGS. 6, 7 and 10, both the upper portion of the housing 75 and the upper portion of the guard 76 are of what may be termed a chamfered configuration having inclined marginal surfaces 78. These inclinedmarginal surfaces 78 serve to ward off or cam upwardly any sagging portion of a cargo unit that may tend to make impact against the housing or guard. FIG. 10 shows the range of translation of the cargopropelling roller 32 between a lower limit position 80 within the boundaries of the housing 75 and an upper limit position 82 at which the roller protrudes sufficiently above the housing to make effective traction contact with cargo items.

The means to operatively connect the motor shaft 52 to the spur gear 55 may comprise reduction gearing in the form of two stages of planetary gearing. In the first stage a sun gear 84 on the motor shaft '52 meshes with first stage planet gears 85 which are mounted on a first stage planet gear carrier 86. The planet'gears 85 mesh with both the first stage sun gear 84 and a first stage ring gear 88. The first stage planet gear carrier 86 is fixedly mounted on a stub shaft 90 which carries a second stage sun gear 92..The second stage sun gear meshes with second stage planet gears 94 which in turn mesh with a second stage ring gear 95. The second stage planet gears 94 are mounted on a second stage planet gear carrier 96 which is keyed to a stub shaft 98 that is journalled in bearings 100 and carries the previously mentioned first spur gear 55.

The two stages of planetary gearing reduces the peripheral speed of the cargo-shifting roller 32 to a suitable rate, which may be approximately 60 feet per minute.

The use of planetary gears for reduction gearing is advantageous in that it permits the combination with the reduction gearing of a torque limiter to protect the mechanism in the event that a cargo item under propulsion by the cargo roller 32 is blocked with consequent abrupt rise in stressing of the parts of the mechanism. For this purpose, the first stage ring gear 88 is mounted on bearings 103 and suitable friction means resists rotation of the ring gear.

In the present embodiment of the invention, as shown in FIGS. and 6, the frictional torque limiting means comprises a pair of arcuate friction shoes 104 which are interconnected by a fixed pivot 105 and are interconnected at their confronting outer ends by means including a screw 106 which provides for adjustment of the pressure with which the shoes grip the ring gear 88. The magnitude 'of the torque that is resisted by the friction shoes is above the nonnal torque output of the motor but is below the torque output augmented by inertia of the motor. When a cargo item being shifted by the roller 32 is suddenly obstructed, the consequent abrupt rise in torque resistance results first in dissipation of power by the friction shoesand then stalling of the motor.

It is to be understood, of course, that any suitable torque limiter may be used within the scope of the invention. For example, with the first stage ring gear 88 permanently immobilized, the stub shaft 98 may be made in two sections 98a and 98b as shown in FIG. a and the two sections may be yieldingly interconnected by a conventional adjustable friction clutch 108.

The construction of the previously mentioned yoke that carries the previously mentioned first and

second latches

36, 38 may be understood by referring to FIGS. 5, 6, 8 and 9. As shown in FIGS. 8 and 9 the yoke 40 has a full-length side plate 110 and two longitudinally spaced shorter

opposite side plates

112 and 114. The'short side plate 1 12 is connected to the longer side plate 110 by a pair of studs 115 which carry corresponding antifriction rollers 117 for cooperation with corresponding fixed upper and lower guide plates 118 shown in FIG. 6. A third stud 119 carries a roller 36 which is the previously mentioned first latch 36. The short side plate 114 is connected to the longer side plate 110 by screws 120 that pass through a spacer block 121 and by a pair of studs 122 that carry corresponding" anti-friction rollers 123. The previously mentioned second latch 38 is a projection of the spacer block 121 between the side plates 110 and 114. The yoke 20 slides on the four anti-friction rollers 117, 123 along the guideway that is formed by guide plates 1 l8.

- To cooperate with the first latch 36 and the second latch 38, the planet gear carrier 22 is fixedly embraced by a sleeve 125 (FIG. 7) with an integral collar 126 that is anchored to the carrier by a radial screw 128. The outer circumferential surface of the collar 126 isconcentric to the axis of rotation of the carrier 22 and, as shown in phantom in FIG. 9, the collar is fonned with the previously described latching recess 35 of the carrier.

As shown in FIG. 5, the mechanism for controlling the yoke 40 comprises the previously mentioned solenoid 44 which has anarmature 130 slidingly mounted in a slide bearing 132. The armature 130 is connected by a pivot 134 to one arm of a bellcrank 135 that is rotatable about a fixed pivot 136. The second arm 138 of the bellcrank extends into a circular aperture 140 of the long side plate 110. As indicated in FIG. 8 the circular aperture 140 may be provided with a bushing 142. The second arm 138 of the bellcrank 135 carries a roller 144 for rolling contact with the bushing 142 to control reciprocation of the yoke 40.

To bias the yoke 40 towards its normal limit position a coil spring 42 which is the previously mentioned spring 42 embraces the armature 130 under compression between the body of the solenoid 144 and a collar 145 that is fixedly mounted on the armature. Thus when the armature is deenergized, the spring 42 is expanded as shown in FIG. 5 to cause the bellcrank 35 to be urged clockwise to hold the yoke 40 in its normal position which is towards the bottom of FIG. 5. At this normal position of the yoke, the pressure of the spring 42 urges the second latch 38 into the latch seat 35 as previously described in reference to FIG. 2. 0n the other hand, when the solenoid is energized, the second latch 38 is retracted and the first latch 35 is advanced towards the collar 126 of the planetgear carrier as heretofore described. It is apparent that the two latches are effective for carrying out the operating cycle regardless of the direction in which the carrier 22 is rotated.

A suitable control circuit for a cargo-shifting unit of the described construction is shown in FIG. 12 wherein a switch 146 operated by a push button 147 closes a direct current circuit 148 to energize the previously mentioned solenoid 44 which, as previously described, mechanically operates the previously described switch 46, and the switch 46 in turn controls a relay 152 for energization of the motor 50. The switch 146 energizes the solenoid 44 as long as the push button 147 is depressed'and incorporates a time delay to keep the solenoid energized for a few seconds after the push button is released. Thus the push button may be momentarily depressed to cause a cargo item to be propelled a few feet. The four leads 154 that terminate at the motor are connected to a reversing relay 155. A toggle switch 156 which may be shifted in opposite directions causes opposite rotations of the motor 50. The push button switch 146 and the toggle switch 156 for the reversing switch are mounted on the same control panel. FIG. 11 shows such a control panel 158 that is pendant on a control cable 159 and further shows a similar fixed control panel 160. The pendant control panel 158 may be moved into and out of the cargo space and may be hung on the wall in the cargo space when not is use.

FIG. 11 shows diagrammatically how the cargo space of an aircraft may be provided with structure of the character disclosed in the Davidson patent, the structure including a set of ball mats 162 in the area opposite the side door opening 164 of the aircraft and further including longitudinal roller trays 165 to move cargo from the ball mats to the front bay of the'cargo space and additional roller trays 166 to facilitate movement of cargo forwardly from the ball mat area.

By way of example of how the present invention may be applied to the structure shown in FIG. 12, a first pair of coaxial powered cargo-propelling rollers 32a are positioned near the doorway 164 to cooperate with the ball elements 168 of the ball mat area to advance cargo items fromthe doorway into the central portion of the ball mat area. The ball mat area further includes two power actuated cargo-propelling rollers 32b with their axis perpendicular to the axis of the aircraft to cooperate with the ball elements 168 to shift cargo items either forward to the roller trays 165 or rearward to the roller trays 166. The forward bay which is provided with the roller trays 165 has a power-actuated cargo-propelling roller 32c to complete the transfer of cargo items from the ball mat area to the bay.

The rearwardly extending portion of the cargo area is provided with a succession of spaced cargo-propelling

rollers

32d, 32e, 32f, etc. to cooperate with the roller trays 166, the successive cargo-propelling rollers being effective in sequence to shift cargo items as far rearward as required. The rectangle 170 with diagonals represents a cargo item stowed in the forward bay and the similar rectangle 171 represents a cargo item in route to the rear end of the cargo space. The control panel 160 that is mounted at a suitable location adjacent the doorway 164 may have two switches, namely a reversing switch to determine the direction of rotation of all of the various cargo-propelling rollers, a push button to control energization of the cargo-propelling rollers 32!; and 32c. The pendant panel 158 may also have two switches, namely, a switch to energize the cargo-propelling roller 32a and a switch to energize the cargo-propelling roller 32b, roller 32b being controlled by either panel. After a foot switch 132d has been operated to energize roller 32d to advance a cargo item rearwardly of the aircraft to the limit of, the range of cargo-propelling roller 32d, the operator may walk into the cargo space and depress a foot switch l72e to energize the cargo-propelling roller 322. In like manner a foot.switch l72f controls the cargo-propelling roller 32f and a foot switch 172g controls the next cargo shifting roller (not shown) etc. It is to be noted that the foot switches are safely remote from the cargo-propelling rollers that they control. The described procedure is safe because the operator is always to the rear of any cargo item that is moving under power.

OTHER APPLICATIONS OF THE INVENTION By way of example of another use for the underlying concept of the invention, FIG. 13 shows a grinding wheel 175 which may be incrementally advanced towards, a workpiece 176 that is reciprocated as indicated by the double arrow 178. The mechanism for driving the grinding wheel on its axis and for shifting the grinding wheel incrementally towards the workpiece 176 comprises the previously described eccentric planetary gear train which includes a planet gear carrier 22a. The planet gear carrier 22a is in the fonn of a worm gear that is controlled by a worm 180 on a control shaft 182. The outer end of the control shaft hasra disk 184 provided with a crank 185 for manual rotation of the control shaft. Suitable means to indicate precisely the degree to which the grinding wheel is advanced partures from my disclosure within the scope of the invention.

I claim:

1. In a cargo handling system for a cargo carrier wherein a plurality of distributed support elements support cargo items at a support plane and are rotatable to minimize frictional resistance to movement of the cargo items along the plane and a plurality of power-actuated rollers are shiftable from lower positions below said plane to upper positions protruding above the plane to engage the bottoms of the cargo items to cooperate with the rotatable support elements to move the cargo items along the support plane,

the improvement comprising each of said rollers being a working part of a corresponding powered unit, said powered unit including:

an input sun gear;

reversible means to actuate the sun gear;

a planet gear carrier with its axis of rotation concentric with the sun gear;

a ring gear unitary with the roller coaxially thereof,

said ring gear being rotatably mounted on the carrier with its axis of rotation offset from the axis of the carrier to cause rotation of the carrier to move the roller in an orbit between its lower position and its upper position;

planet gear means on the carrier in mesh with both the sun gear and the ring gear; and

means to rotate the carrier for orbital movement of the roller.

2. An improvement as set forth in claim 1 which includes means to releasably immobilize the carrier at the upper position of the roller.

3. An improvement as set forth in claim I in which said ring gear is of cylindrical configuration and is united with the roller inside the roller;

and in which said sun gear, said carrier and said planet. gear means all extend longitudinally of the roller inside the roller.

4. An improvement as set forth in claim 1 in which said planet gear means includes at least one pair of axially spaced coaxial planet gears.

5. An improvement as set forth in claim 1 in which said reversible means to actuate the sun gear is a motor;

which includes a remote switch to control energization of the motor;

and which includes remote means to control the direction of rotation of the motor.

6. An improvement as set forth in claim 5 in which said remote switch creates a signal to energize the motor and incorporates means to delay de-energization of the motor when the remote switch is operated.

7. An improvement as set forth in claim 1 which includes means to limit the torque transmitted to the sun gear to a given magnitude above the magnitude of the normal driving torque of the motor but below a destructive magnitude in the event that the movement of a cargo item is blocked while the motor is energized.

8. An improvement as set forth in claim 4 which includes reduction gearing to transmit torque to the sun gear and in which said torque limiting means is combined with the reduction gearing.

9. An improvement as set forth in claim 8 in which the reduction gearing includes a planetary gear train comprising a sun gear, a planet gear carrier, a ring gear and a planet gear on the carrier in mesh with both the sun gear and the ring gear;

and in which the torque limiting means frictionally opposes rotation of the ring gear of the reduction gearing.

1 0. An improvement as set forth in claim 1 which includes means to cause power flow from the sun gear to the planet gear carrier to rotate the planet gear carrier to shift the roller between its lower and upper positions.

11. An improvement as set forth in claim which includes means responsive to energization of the sun gear to latch the carrier in response to movement of the roller to its upper position and to release the carrier in response to deenergization of the sun gear to permit the momentum of the rotating parts to rotate the carrier to shift the roller from its upper position to its lower position.

12. An improvement as set forth in claim 11 which includes a second latch biased to latch the carrier in response to rotation of the carrier at the lower position of the roller after the motor is de-energized, said second latch being releasable in response to energization of the motor.

13. An improvement as set forth in claim 11 which includes a housing enclosing moving parts of the unit;

and in which the portions of the sun gear and the carrier protrude to the exterior of the housing with the ring gear mounted on the protruding portion of the carrier and with the roller encasing the ring gear.

14. An improvement as set forth in claim 10 in which the upper portion of the housing is of chamfered configuration to minimize head-on impact against the housing of cargo items that protrude downwardly from said plane.

15. An improvement as set forth in claim 12 which includes guard means below said plane adjacent the roller to protect the roller at the lower position of the roller.

16. An improvement as set forth in claim 15 in which the upper portion of the guard means is of chamfered configuration to minimize head-on impact against the guard means of cargo items that protrude downwardly from said plane.

17. An improvement as set forth in claim 1 in which the floor of the cargo carrier is equipped with seat rails;

in which said unit has two longitudinally spaced means for releasable attaching the unit to a seat rail longitudinally thereof;

and in which said unit has two laterally spaced means for releasable attachment to a seat rail with the unit positioned transversely of the seat rail. 18. In a system for handling objects such as cargo items, wherein the system includes support structure of open construction to support the objects at a support plane,

the combination therewith of: at least one roller movable bodily through the open support structure between a retracted position below said plane and an effective position protruding above the plane to engage the bottoms of the objects to move the objects across the support structure; c

a single drive means to power the roller; and

control means operable in a first respect to cause the drive means to shift the roller between its two positions and operable in a second respect to operatively connect the drive means to the roller to rotate the roller on its axis when the roller is in its effective position.

19. A combination as set forth in claim 18 in which the roller is hollow with inner circumferential gear teeth;

in which drive means extends from the power means into theinterior of the roller;

which includes means responsive to the operation of the control means in its first respect to cause said drive means to shift the roller between its two positions; and which includes means responsive to operation of the control means in its second respect to operatively connect the power means to said inner teeth to rotate the roller on its axis.

20. In a system for handling objects such as cargo items, wherein the system includes support structure of open construction to support the objects at a support plane,

the combination therewith of:

at least one hollow roller movable bodily through the open support structure between a retracted position below said plane and an effective position protruding above the plane to engage the bottoms of the objects to move the objects across the support structure;

power actuated means extending into the interior of the hollow roller from one end thereof;

remotely controlled means to operatively connect the power actuated means to the roller to shift the roller between its two positions; and

remotely controlled means to operatively connect the power actuated means to the roller to rotate the roller on its axis when the roller is in its effective position.

21. A combination as set forth in claim 20 which includes means inside the hollow roller to guide the hollow roller on an arcuate path between its two positions.

22. In a system for handling objects such as cargo items, wherein the system includes support structure of open construction to support the objects at a support plane,

the combination therewith of:

at least one roller movable bodily in a circular orbit through the open support structure between a retracted position below said plane and an effective position protruding above the plane to engage the bottoms of the objects to move theobjects across the support structure with the axis of the orbit offset from the axis of rotationof the roller;-

power means for the roller; and a control means operable in a first respect to cause the power means to shift the roller through one-half of its orbit between its two positions and operable in a second respect to operatively connect the power means to the roller to rotate the roller on its axis when the roller is in its effective position.

23. In a system for handling objects such as cargo items, wherein the system includes support structure of open construction to support the objects at a support plane, I

the combination therewith ofz at least one hollow roller with inner circumferential pear teeth movable bodily through the open support structure between a retracted position below said plane and .an efieetive position protruding above the plane to engage the bottoms of the objects to move the objects across the support structure;

power means for the roller;

control means operable in a first respect to cause the power means to shift the roller between its two positions and operable .in a second respect to operatively connect the power means to the roller to rotate the roller on its axis when the roller is in its effective position,

drive means extending from the power means into the interior of the roller;

means responsive to the operation of the control means in its first respect to cause said drive means to shift the roller between its two positions;

means responsive to operation of the control means in its second respect to operatively connect the power means to said inner teeth to rotate the roller on its axis;

gearing inside the hollow roller, said gearing including a first gear on the axis of the orbit and a second gear in mesh both with the first gear and with said inner circumferential teeth of the roller; means responsive to operation of said control means in its first respect to walk said second gear around the first gear between a first position and a second position of the second gear to shift the roller between its retracted position and its effective position; and means responsive to the operation of the control means in its second respect to rotate the first gear while the second gear is in one of its two positions thereby to act through the second gear to rotate 'the roller on its axis.

l t t l l

Claims

1. In a cargo handling system for a cargo carrier wherein a plurality of distributed support elements support cargo items at a support plane and are rotatable to minimize frictional resistance to movement of the cargo items along the plane and a plurality of power-actuated rollers are shiftable from lower positions below said plane to upper positions protruding above the plane to engage the bottoms of the cargo items to cooperate with the rotatable support elements to move the cargo items along the support plane, the improvement comprising each of said rollers being a working part of a corresponding powered unit, said powered unit including: an input sun gear; reversible means to actuate the sun gear; a planet gear carrier with its axis of rotation concentric with the sun gear; a ring gear unitary with the roller coaxially thereof, said ring gear being rotatably mounted on the carrier with its axis of rotation offset from the axis of the carrier to cause rotation of the carrier to move the roller in an orbit between its lower position and its upper position; planet gear means on the carrier in mesh with both the sun gear and the ring gear; and means to rotate the carrier for orbital movement of the roller.

3. An improvement as set forth in claim 1 in which said ring gear is of cylindrical configuration and is united with the roller inside the roller; and in which said sun gear, said carrier and said planet gear mEans all extend longitudinally of the roller inside the roller.

5. An improvement as set forth in claim 1 in which said reversible means to actuate the sun gear is a motor; which includes a remote switch to control energization of the motor; and which includes remote means to control the direction of rotation of the motor.

9. An improvement as set forth in claim 8 in which the reduction gearing includes a planetary gear train comprising a sun gear, a planet gear carrier, a ring gear and a planet gear on the carrier in mesh with both the sun gear and the ring gear; and in which the torque limiting means frictionally opposes rotation of the ring gear of the reduction gearing.

10. An improvement as set forth in claim 1 which includes means to cause power flow from the sun gear to the planet gear carrier to rotate the planet gear carrier to shift the roller between its lower and upper positions.

11. An improvement as set forth in claim 10 which includes means responsive to energization of the sun gear to latch the carrier in response to movement of the roller to its upper position and to release the carrier in response to deenergization of the sun gear to permit the momentum of the rotating parts to rotate the carrier to shift the roller from its upper position to its lower position.

13. An improvement as set forth in claim 11 which includes a housing enclosing moving parts of the unit; and in which the portions of the sun gear and the carrier protrude to the exterior of the housing with the ring gear mounted on the protruding portion of the carrier and with the roller encasing the ring gear.

17. An improvement as set forth in claim 1 in which the floor of the cargo carrier is equipped with seat rails; in which said unit has two longitudinally spaced means for releasable attaching the unit to a seat rail longitudinally thereof; and in which said unit has two laterally spaced means for releasable attachment to a seat rail with the unit positioned transversely of the seat rail.

18. In a system for handling objects such as cargo items, wherein the system includes support structure of open construction to support the objects at a support plane, the combination therewith of: at lEast one roller movable bodily through the open support structure between a retracted position below said plane and an effective position protruding above the plane to engage the bottoms of the objects to move the objects across the support structure; a single drive means to power the roller; and control means operable in a first respect to cause the drive means to shift the roller between its two positions and operable in a second respect to operatively connect the drive means to the roller to rotate the roller on its axis when the roller is in its effective position.

19. A combination as set forth in claim 18 in which the roller is hollow with inner circumferential gear teeth; in which drive means extends from the power means into the interior of the roller; which includes means responsive to the operation of the control means in its first respect to cause said drive means to shift the roller between its two positions; and which includes means responsive to operation of the control means in its second respect to operatively connect the power means to said inner teeth to rotate the roller on its axis.

20. In a system for handling objects such as cargo items, wherein the system includes support structure of open construction to support the objects at a support plane, the combination therewith of: at least one hollow roller movable bodily through the open support structure between a retracted position below said plane and an effective position protruding above the plane to engage the bottoms of the objects to move the objects across the support structure; power actuated means extending into the interior of the hollow roller from one end thereof; remotely controlled means to operatively connect the power actuated means to the roller to shift the roller between its two positions; and remotely controlled means to operatively connect the power actuated means to the roller to rotate the roller on its axis when the roller is in its effective position.

22. In a system for handling objects such as cargo items, wherein the system includes support structure of open construction to support the objects at a support plane, the combination therewith of: at least one roller movable bodily in a circular orbit through the open support structure between a retracted position below said plane and an effective position protruding above the plane to engage the bottoms of the objects to move the objects across the support structure with the axis of the orbit offset from the axis of rotation of the roller; power means for the roller; and control means operable in a first respect to cause the power means to shift the roller through one-half of its orbit between its two positions and operable in a second respect to operatively connect the power means to the roller to rotate the roller on its axis when the roller is in its effective position.

23. In a system for handling objects such as cargo items, wherein the system includes support structure of open construction to support the objects at a support plane, the combination therewith of: at least one hollow roller with inner circumferential pear teeth movable bodily through the open support structure between a retracted position below said plane and an effective position protruding above the plane to engage the bottoms of the objects to move the objects across the support structure; power means for the roller; control means operable in a first respect to cause the power means to shift the roller between its two positions and operable in a second respect to operatively connect the power means to the roller to rotate the roller on its axis when the roller is in its effective position, drive means extending from the power means into the interior of the roller; means responsive to the operatiOn of the control means in its first respect to cause said drive means to shift the roller between its two positions; means responsive to operation of the control means in its second respect to operatively connect the power means to said inner teeth to rotate the roller on its axis; gearing inside the hollow roller, said gearing including a first gear on the axis of the orbit and a second gear in mesh both with the first gear and with said inner circumferential teeth of the roller; means responsive to operation of said control means in its first respect to walk said second gear around the first gear between a first position and a second position of the second gear to shift the roller between its retracted position and its effective position; and means responsive to the operation of the control means in its second respect to rotate the first gear while the second gear is in one of its two positions thereby to act through the second gear to rotate the roller on its axis.