Legless locker shelf assembly
FIELD OF INVENTION 
     The technical field of the invention is shelf structures used in storage lockers, including school lockers. 
     BACKGROUND OF THE INVENTION 
     Storage lockers are used in a number of environments such as industrial, commercial, military and educational institutions for temporary storage of personal items such as clothing, books, sporting equipment and the like. An example of a knock-down locker is shown by Novales in U.S. Pat. No. 3,360,321. This locker has a top shelf permanently attached to the locker side walls. The shelf has a fixed length and fits into a specific size locker. Boards and plywood panels have been used as auxiliary or additional locker shelves. The panels are made slightly wider than the width of the locker so that they can be wedged against the locker side walls to hold them in a selected vertical position. The wedging of the panels against the side walls distorts and bends the locker side walls and the door frame. In some cases, the door frame is warped so that the locker door cannot be closed. Lockers are normally located in side-by-side locations such as found in schools. When one locker is distorted, the adjacent locker is also distorted. This can cause the locker doors to jam shut or prevent the locker doors from closing. R. R. Peterson in U.S. Pat. No. 4,500,146 discloses a laterally adjustable locker shelf assembly having a plurality of locker shelves mounted on upright legs. Each locker shelf can be laterally expanded to position the locker shelf assembly within a locker. The locker shelf assembly of the invention is an expandable shelf assembly that does not utilize support legs to locate the shelf assembly within a locker. 
     SUMMARY OF THE INVENTION 
     The invention is directed to a legless locker shelf assembly that can be positioned within the locker at a selected location for accommodating articles, such as clothing, books, tools, sporting equipment and the like. The locker is a conventional locker used in schools, homes, sports clubs, industrial and office environments. The legless locker shelf assembly is an independent laterally adjustable shelf unit that fits into the locker and is forced against opposite locker side walls and retained therein with dual locking structure. The legless locker shelf assembly is a self contained unit as it does not require any assembly at the locker and is convenient and easy to install. Once the locker shelf assembly is expanded to its selected location, it is a strong, durable structure that can support considerable loads without the use of legs or support rods or connectors, such as bolts and screws, attaching the shelf to the locker walls. 
     One form of the shelf assembly has first and second shelf members having overlapping top walls and side walls that are movable relative to each other to change the longitudinal length of the shelf assembly. Adjacent side walls of the shelf members have engaging rachet teeth allowing opposite outward movements of the shelf members to expand the shelf assembly and prevent inward movements of the shelf members. The rachet teeth are releasable from each other by flexing the adjacent side walls in opposite directions to disengage the rachet teeth whereby the shelf members can be moved toward each other to contract the shelf assembly. Guides and supports on the shelf members maintain the shelf members in general longitudinal alignment and allow relative longitudinal alignment and allow relative longitudinal movement of shelf members. A plurality of longitudinally spaced cam follower teeth are attached to the top wall of the first shelf member. A cam actuator having a spiral-shaped outer edge is rotatably mounted on a boss attached to the second shelf member with the outer edge in engagement with at least one tooth. The outer edge has an inner portion and an outer portion located in overlapping relation and radially outward from the inner portion a distance substantially equal to the distance between adjacent teeth of the cam follower teeth so that the outer edge is in continuous engagement with at least one tooth upon rotation of the cam actuator to expand the shelf assembly and lock the shelf assembly in the expanded position. The boss is inclined at a small angle relative to the plane of the top wall of the second shelf member to tilt the cam actuator inwardly toward the cam follower teeth and maintain one portion of the outer edge in engagement with one tooth of the cam follower teeth. 
     Another form of the invention is an apparatus for expanding first and second members having cooperating structures for maintaining the members in general longitudinal alignment with each other and allowing relative longitudinal movements of the members. One of the members has longitudinal-spaced cam follower teeth that are engaged with a rotatable cam actuator. The cam actuator has a spiral-shaped outer edge engageable with at least one tooth of the cam follower teeth so that on rotation of the cam actuator, the members expand in opposite directions and are retained in their expanded positions. The outer edge has an inner portion and an outer portion located in overlapping relation and radially outward from the inner portion a distance substantially equal to the distance between adjacent teeth of the cam follower teeth so that the outer edge is in continuous engagement with at least one tooth of the cam follower teeth upon rotation of the cam actuator to expand the members and lock the members in the expanded position. The cam actuator is rotatably mounted on an inclined boss which tilts the cam actuator inwardly toward the cam follower teeth and maintains one portion of the outer edge in engagement with one tooth of the cam follower teeth. 
    
    
     DESCRIPTION OF THE DRAWING 
     FIG. 1 is a perspective view of a group of lockers showing one of the lockers accommodating the legless locker shelf assembly of the invention; 
     FIG. 2 is an enlarged sectional view taken along the line 2--2 of FIG. 1; 
     FIG. 3 is a perspective view of the legless locker shelf assembly shown in FIG. 1; 
     FIG. 4 is a top plan view of the legless locker shelf assembly of FIG. 3; 
     FIG. 5 is an end elevational view of the legless locker shelf assembly viewing along line 5--5 of FIG. 4; 
     FIG. 6 is an end elevational view of the legless locker shelf assembly viewing along line 6--6 of FIG. 4; 
     FIG. 7 is a side elevational view of the legless locker shelf assembly viewing along the line 7--7 of FIG. 4; 
     FIG. 8 is a bottom plan view of the legless locker shelf assembly showing the cam actuator in the position to expand the shelf assembly; 
     FIG. 9 is a bottom plan view of the legless locker shelf assembly showing the cam actuator in the position to allow the shelf assembly to contract; 
     FIG. 10 is a sectional view taken along the line 10--10 of FIG. 8; 
     FIG. 11 is a sectional view taken along the line 11--11 of FIG. 9; and 
     FIG. 12 is a sectional view taken along the line 12--12 of FIG. 8. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENT 
     Referring to FIGS. 1 and 2, there is shown a conventional locker indicated generally at 10, normally used by one or more persons for safe keeping clothing, books, tools, sporting goods and like articles. Locker 10 has upright side walls 11 and 12 joined to an upright back wall 13. The lower part of the locker 10 has a bottom or floor 14. The top of the locker is covered with a top wall 15. The front of the locker has a generally rectangular door frame 16 providing a doorway 17 into the interior of the locker. A generally rectangular door 16 is movably mounted on frame 16 with a plurality of hinges 19. A releasable lock or latch 21 on the door is used to retain the door in the closed position. 
     A legless locker shelf assembly of the invention, indicated generally at 22, is positioned within locker 10. Locker shelf assembly 22 has a pair of shelf members indicated generally at 23 and 24 that are laterally movable relative to each other so that locker shelf assembly 22 can be expanded into a tight holding position against the side walls 11 and 12, as seen in FIG. 2. Legs or other support structures are not used to hold locker shelf assembly 22 within locker 10. 
     As seen in FIGS. 3, 4 and 5, shelf member 23 has a generally flat top wall 26 joined to downwardly directed side walls 27 and 28 and a transverse outer end wall 29. The upper portion of end wall 29 has an upwardly directed transverse lip 31 to retain small articles on top wall 26. Top wall 26 has a pair of longitudinal grooves 32 and 36 having longitudinal slots 33 and 37, respectively extended between opposite ends of wall 26. As seen in FIG. 4, slot 33 has an outer end 34 which is transversely enlarged adjacent lip 31. A similar enlarged end 38 extends across slot 37 adjacent lip 31. The mid portion of wall 26 has a longitudinal slot 39 interrupted with a plurality of diagonal openings 41. 
     As seen in FIG. 8, side wall 27 has a plurality of longitudinally arranged teeth 42 that slope inwardly in a rearward direction. Side wall 28 has similar teeth 43 that are in transverse alignment with teeth 42 and slope inwardly in a rearward direction. The backs of teeth 42 and 43 slope inwardly and rearwardly away from end wall 29. The inner portions of side walls 27 and 28 have downwardly directed tabs 44 and 46. Tab 44 has an inwardly directed shoulder 45. Tab 46 has a similar inwardly directed shoulder 50. The functions of shoulders 45 and 50 are hereinafter described. The bottom of wall 26 has longitudinal side ribs 47 and 48 and a central longitudinal rib 49. Slot 37 extends longitudinally along rib 47. Slot 33 extends longitudinally along rib 48. Rib 49 is interrupted with a plurality of angularly longitudinally spaced teeth or cam followers 51. Each of teeth 51 are inclined at an angle of about 105 degrees relative to the longitudinal length of rib 49. Other angles of teeth 51 can be used. As shown in FIG. 10, each tooth 51 has an inwardly directed angular lip 52. 
     A pair of buttons 53 and 54 of rubber or plastic material are secured to opposite end portions of transverse wall 29. As seen in FIG. 2, buttons 53 and 54 are located in tight frictional engagement with side wall 11 when the shelf assembly is located within locker 10. 
     Returning to FIG. 3, shelf member 24 has a generally flat top wall 56 joined to downwardly directed longitudinal side walls 57 and 58. Side walls 57 and 58 are connected to an outside end wall 59 and an inside end wall 60. Outside end wall 59 has an upwardly directed lip 61 to retain small items on top wall 56. End wall 59 supports a pair of buttons 62 and 63 of plastic or rubber-like material adapted to be forced into tight frictional engagement with side wall 12, as seen in FIG. 2, when the shelf assembly is located within locker 10. 
     Returning to FIG. 4, top wall 56 has a pair of lateral longitudinal grooves 64 and 66 and a longitudinal center groove 67. Grooves 64 and 66 slideably accommodate ribs 47 and 48 to laterally guide shelf members 23 and 24 relative to each other. Center groove 67 accommodates rib 49. The structure that provides grooves 64, 66 and 67 are longitudinal ribs 68, 69 and 71, as seen in FIGS. 8 and 12. 
     Side walls 57 and 58 of shelf member 24 have outwardly directed rachet teeth 72 and 73 which cooperate with the inwardly directed rachet teeth 42 and 43 of the side walls 27 and 28 of shelf member 23. Rachet teeth 72 and 73 slope inwardly in an outward direction toward end wall 59. As seen in FIG. 6, shoulders 45 and 50 are located below and in engagement with the lower edges of side walls 57 and 58 of shelf assembly 24 to provide supports for side walls 57 and 58 and retain rachet teeth 42, 73 and 43, 72 in engagement with each other. 
     Returning to FIGS. 3 and 4, a pair of necks 74 and 77 are secured to transverse wall 60 and extend through the slots 33 and 37. The outer ends of necks 74 and 77 have cross heads 76 and 78 located in grooves 32 and 36. When shelf members 23 and 24 are in their collapsed positions, cross heads 76 and 78 are located in alignment with the enlarged ends 34 and 38 at the outer ends of grooves 33 and 37. Cross heads 76 and 78 can move through openings 34 and 38 to allow shelf members 23 and 24 to be separated from each other and operatively connected to each other. No parts are removed from shelf members 23 and 24 to separate the shelf members or install the shelf assembly within locker 10. 
     Referring to FIGS. 8-12, there is shown a cam actuator indicated generally at 79 operable to expand shelf members 23 and 24 relative to each other and lock the shelf members in their expanded positions in tight holding engagement with side walls 11 and 12. Actuator 79 has a cylindrical hub 81 that surrounds a cylindrical boss 83 joined to wall 56 of shelf member 24. Boss 83 has upwardly directed flexible fingers 82 that extend over an outwardly directed annular rib 84 on hub 81 to retain the cam actuator in rotatable assembled relation with wall 56. Boss 83 extends downwardly and inwardly at a small angle of 5 degrees relative to the plane of wall 56 so that the actuator 79 is tilted in an inward direction toward transverse wall 60. Actuator 79 can be tilted at other angles. Actuator 79 has a downwardly directed knob 86 providing a convenient hand grip for the operator used to rotate the actuator. The lower portion of knob 86 has an outwardly directed flange 87 having a spiral outer edge 88. Edge 88 has an inner portion 89 that is overlapped with an outer portion 91 so that both the inner and outer portions 89 and 91 of edge 88 simultaneously engage teeth 51A and 51B. The overlap of edge portions 89 and 91 is about 10 degrees. The circumferential length of the edge is about 370 degrees. Other amounts of overlap can be used. The radial distance between end portion 89 and outer end portion 91 is substantially equal to the longitudinal distance between the adjacent teeth 51A and 51B. 
     In use, locker shelf assembly 22 is moved to its contracted position. As shown in FIG. 9, actuator 79 is moved in a counter clockwise direction, as indicated by arrow 96 to release edge 88 from teeth 51A and 51B. Tabs 44 and 46 are then forced outwardly to release the cooperating rachet teeth 42, 73 and 43, 72. Shelf members 23 and 24 can then be pivoted relative to each other to allow necks 74 and 77 to slide in grooves 33 and 37 to move cross heads 76 and 78 to end openings 34 and 38. Shelf members 23 and 24 are then moved to their generally longitudinal alignment to locate the rachet teeth 42, 73 and 43, 72 in rachet alignment and shoulders 45 and 50 under the lower edges of side walls 11 and 12 and end 58 thereby maintaining the longitudinal alignment of shelf members 23 and 24. Shelf assembly 22 is now in its contracted or small position. 
     The contracted locker shelf assembly 22 is placed in the locker chamber as shown in FIGS. 1 and 2. End walls 29 and 59 are located adjacent side walls 11 and 12 of the locker. Actuator 79 is then rotated in a clockwise direction, as indicated by arrow 92 in FIG. 8. Edge 88 engages a tooth 51A below lip 52 and moves the teeth and shelf members 23 and 24 in opposite outward directions. Actuator 79 is rotated a complete turn to advance shelf member 23 the distance between adjacent teeth. Edge portion 89 will pick up a tooth 51B before edge portion 91 moves away from a tooth 51A so that continuous rotation of actuator 79 in a clockwise direction will continuously move shelf members 23 and 24 in opposite outward directions. During the movement of shelf members 23 and 24 in opposite outward directions, the cooperating rachet teeth 42, 73 and 43, 72 will sequentially override cooperating teeth and prevent the contraction of shelf members 23 and 24 relative to each other. Actuator 79 is continuously rotated until the resilient buttons 53, 54 engage locker wall 11 and resilient buttons 62 and 63 engage locker wall 12. Buttons 53, 54, 62 and 63 are retained in tight compressed frictional engagement with walls 11 and 12 by continuing the rotation of actuator 79 in a clockwise direction, as indicated by arrow 92 in FIG. 8. Locker shelf assembly 22 is maintained in the expanded position by locking functions of the cooperating rachet teeth 42, 73 and 43, 72 and cam actuator 79 in engagement with a rachet tooth 51. 
     Legless locker shelf assembly 22 can be released from holding engagement with the locker side walls 11 and 12 by rotating actuator 79 in a counter clockwise direction, as indicated by arrow 96 to release edge 88 from it in engagement with tooth 51. Tabs 44 and 46 are then moved in an outward direction to release the interlocking rachet teeth 42, 73 and 43, 72 thereby allowing shelf members 23 and 24 to move toward each other to contract the shelf assembly. No assembly is required to install or remove the shelf assembly from a locker. 
     While there has been shown and described a preferred embodiment of the legless shelf assembly of the invention, it is understood that changes in the structure, arrangement of structure and materials can be made by those skilled in the art without departing from the invention. The invention is defined in the following claims.