Abstract:
A cleat with automatic line-locking, includes a frame having proximate and remote sides and formed with a passageway, extending between the proximate and remote sides, for receiving a line for movement along a first line moving direction from the proximate to the remote sides and an opposing line pulling direction from the remote to the proximate sides, and defining a line bearing surface or limit stop on one side of the passageway for limiting excessive transverse movements of the line in a direction to the one side of the passageway. Fasteners attach the frame to a support surface. A cam is provided on the frame on the other or opposite side of said passageway and has a line engaging portion normally spaced a predetermined distance from the line. The cam is movable between a line releasing position and a line locking position and is arranged to normally disengage from the line, engagement of the line by the cam to the line locking position while advancing the line in the first line moving direction creating a force couple that wedges the line between the line bearing surface or limit stop and the cam that tends to arrest or stop the line relative to the frame fixed on the support surface. The cam is formed of generally flat sheet material defining a cam plane and the line engaging portion being formed of a plurality of generally flat pressure-engaging segments or pressure pads that are angularly offset to opposite sides of said cam plane and together generally defining a line-receiving region having a generally uniform cross-section configured to frictionally engage the line in the line locking position. Auxiliary sheave assemblies may be used to provide automatic failsafe operation by means of the cleat when raising or lowering an object on a hook or loop. A pusher may be used to urge the line to move in the direction of the cam especially when the line is released.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a continuation application of International Application No. PCT/US2009/006474 with an international filing date of Dec. 7, 2009, currently pending, which claims priority of U.S. Provisional Patent Application No. 61/201,817 filed on Dec. 15, 2008 and U.S. Provisional Patent Application No. 61/276,923 filed on Sep. 18, 2009. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention generally relates to line control devices and, more specifically to a failsafe system raising and lowering at least one object. 
         [0004]    2. Description of the Prior Art 
         [0005]    One traditional or common device for securing a line from advancing relative to a reference point is a cam cleat that includes a support structure through which the line passes and one or two pivotally mounted cams within the structure that can move between a first position in which the cam(s) permits the line to move along a given direction and a second position in which the cam(s) engages the line by applying pressure to it to prevent the line from advancing in an opposite direction with respect to a support structure. 
         [0006]    Known cams generally have had a thickness that substantially corresponded to the diameter of the line and have been provided with a series of spaced teeth or ridges that are generally transverse to the direction of movement of the line. When the movement of the line needed to be halted the cam was rotated to contact the line and the teeth penetrated and deformed the line within a confined passageway to create a pressure and/or friction that prevented the line from advancing. However, traditional cleats of this type have a number of disadvantages. For example, such cleats normally require numerous operative parts, including a spring that normally urges the cam to be biased into contact with the line. As such, the line must normally be manually inserted into the cleat by moving the cam to a non-locking position against the action of the spring. The need for numerous working parts makes the cleat more costly to manufacture and more susceptible to failure. Assembly of the cleat and its numerous parts contributes to the high cost of manufacture. 
         [0007]    Because the cams typically have a thickness that approximates the diameter of the line being controlled such cleats tend to be large and bulky. Also, the cams need to be molded or cast to provide the desired cam thicknesses and, thus, cannot be made of relatively thin sheet material. Also, a serious problem is the damage that traditional cleats cause to the lines that are controlled. Because the lines are locked in place when the relatively sharp teeth edges or ridges of the cams penetrate and deform the lines by applying substantial transverse forces that bite across the fibers or strands of the line, the sharp teeth frequently damage the strands or fibers forming the lines by and, with time, the teeth of the cams deteriorate the integrity of the strands or fibers and, therefore, also of the lines as well. Repeated or continued uses of the cleat frequently render the lines unsuitable for extended use. This not only jeopardizes the operation and safety of the apparatus on which the cleat is used, such as a machine or sailboat, for example, but also requires regular replacements of the lines. This is a further inconvenience and costly operation. 
         [0008]    In U.S. Patent Application No. 61/201,817, assigned to the assignee of the subject application, a cam formed of planar material and devices using the same are disclosed. However, the pulley or sheave is not always optimum for desired applications, including systems for raising and lowering potted plants, bicycles and other objects as they are not constructed from an optimal number of reduced parts or components. Such construction(s) increase the costs of manufacture and hence the cost to the consumer. Also, some of the components described in the aforementioned application are sometimes difficult or inconvenient to mount onto a ceiling or a wall. 
       SUMMARY OF THE INVENTION 
       [0009]    It is an object of the invention to provide a novel system for raising and lowering objects. 
         [0010]    It is another object of the invention to provide such a system that does not have the disadvantages of know cams used for line control. 
         [0011]    It is still another object of the invention to provide such a system as in the previous objects that is formed of flat sheet material. 
         [0012]    It is yet another object of the invention to provide such a system of the type suggested in the previous objects that can be formed by die cutting or stamping. 
         [0013]    It is still another object of the invention to provide such a system that has a thin profile and can be housed in a narrow profile support structure. 
         [0014]    It is yet another object of the invention to provide such a system that can provide effective frictional engagement with a line without unduly penetrating or deforming the line when secured against movement. 
         [0015]    It is an additional object of the invention to provide such a system that provides a frictional line-engaging surface that does not damage the strands or fibers within a line thereby increasing the useful life of the line and avoids the need to regularly or frequently replace the line. 
         [0016]    It is still an additional object of the invention to provide a simplified pulley or sheave construction that minimizes or reduces the number of components for assembly and that, therefore, reduces the cost thereof. 
         [0017]    It is also an object of the invention to provide a cleat-block within a system of the previous objects for raising and lowering objects. 
         [0018]    It is also an additional object of the invention to provide a system that is simple and convenient for mounting on a ceiling or wall and only requires the most basic of tools. 
         [0019]    In order to achieve the above objects, and others that will become apparent hereafter, a system for raising and lowering objects includes a cleat for selectively locking and releasing an elongate member in accordance with the invention comprises a support member having two generally opposing ends and an internal channel extending between said opposing ends along a predetermined direction and dimensioned for passage of an elongate member, such as a line, there-through. Said support member has a cavity proximate to said channel and communicates therewith. A cam within said cavity comprises a generally flat portion defining a cam plane and has pivot means about which the cam can pivot within said cam plane and defines a generally arcuate peripheral portion spaced from said pivot means. Engaging means along said arcuate peripheral portion for engaging an elongate member generally extends within said cam plane and applies incremental pressures to the elongate member to urge the elongate member against a generally fixed surface with movements of the cam from a first non-engaging position to a second locking position as the cam pivots about said pivot means. The engaging means includes pressure-applying pads extending from said flat portion along said arcuate peripheral portion to both sides of said cam plane to define an engaging surface that generally conforms to the exterior shape of the elongate member. 
         [0020]    Preferably, the cleat with automatic line-locking comprises a frame having proximate and remote sides and formed with a passageway, extending between said proximate and remote sides, for receiving a line for movement along a first line moving direction from said proximate to said remote sides and an opposing line pulling direction from said remote to said proximate sides, and defining a line bearing surface or limit stop on one side of said passageway for limiting excessive transverse movements of the line in a direction to said one side of said passageway. Cam means is provided on said frame on the other or opposite side of said passageway and has a line engaging portion normally spaced a predetermined distance from the line, said cam means being movable between a line releasing position and a line locking position, said cam means being arranged to normally disengage from the line, engagement of the line by said cam means to said line locking position while advancing the line in said first line moving direction from said proximate to said remote sides creating a force couple that wedges the line between said line bearing surface or limit stop and said cam that tends to arrest or stop the line relative to said frame fixed on the support surface. Said cam means is formed of generally flat sheet material defining a cam plane and said line engaging portion being formed of a plurality of generally flat pressure-engaging segments or pressure pads that are angularly offset to opposite sides of said cam plane and together generally defining a line-receiving region having a generally uniform cross-section configured to frictionally engage the line in said line locking position. 
         [0021]    A self-actuating cleat for automatically arresting the movement of an elongate member, such as a line, when the tension within the elongate member drops below a predetermined or threshold value in accordance with the invention comprises a support member having two generally opposing ends and an internal channel extending between said opposing ends along a predetermined direction and dimensioned for passage of the elongate member there-through. Said support member has a cavity proximate to said channel and communicates therewith. A cam within said cavity comprises a generally flat portion defining a cam plane and has pivot means about which the cam can pivot within said cam plane and defines a generally arcuate peripheral portion spaced from said pivot means. Engaging means along said arcuate peripheral portion for engaging the elongate member generally extends within said cam plane and applies incremental pressures to the elongate member to urge the elongate member against a generally fixed surface with movements of the cam from a first non-engaging position to a second locking position as the cam pivots about said pivot means. Said engaging means includes pressure applying pads extending from said flat portion along said arcuate peripheral portion to both sides of said cam plane to define an engaging surface that generally conforms to the exterior shape of the elongate member. First biasing means normally urges said cam to said first non-engaging position. Second biasing means normally urges the elongate member into engagement with said cam only when the tension in the elongate member is below said predetermined tension. Said first biasing means releases said cam when an advancing elongate member engages said cam to urge said cam to move from said first non-engaging position to said second engaging position. 
         [0022]    Other devices using the novel cam can be used in a multitude of devices where line control is important, such as on sailing yachts, raising and lowering objects such as potted plants, bicycles and the like. Improved mounting hardware and auxiliary sheave constructions reduce the number of components and simplifies assembly and thus reduce the costs of manufacture. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]    These and other objects will become apparent when the present invention is considered in detail in the below specification, taken in conjunction with the drawings as follows: 
           [0024]      FIG. 1   a  is a side elevational view of a failsafe system to raise and lower objects in accordance with the present invention, shown partially in cross-section to illustrate the path of the control line and the details of mounting on a ceiling; 
           [0025]      FIG. 1   b  is a cross-sectional view of the cleat shown in  FIG. 1   a , taken along line  1   b - 1   b , and also showing an enlarged region A to illustrate the construction of a fastener for mounting the cleat onto a ceiling; 
           [0026]      FIG. 1   c  is a cross-sectional view of the cleat shown in  FIG. 1   a , taken along line  1   c - 1   c , and also showing enlarged regions B and C to illustrate the construction or assembly details of the clamshells forming the housing of the cleat and also for retaining the fastener for attaching the cleat to a ceiling; 
           [0027]      FIG. 1   d  is a side elevational view of the cleat shown in  FIG. 1   a , shown mounted on a wall; 
           [0028]      FIG. 1   e  is similar to  FIG. 1   d , but illustrating the use of a different mounting fastener for mounting the cleat onto a vertical support member by using a threaded bolt and nut; 
           [0029]      FIG. 2  is an exploded view of the sheave wheel used in the cleat of  FIG. 1   a  separated from the pusher element that is normally pivotally mounted on the same pin or shaft that the sheave wheel is rotatably mounted on; 
           [0030]      FIG. 3   a  is a side elevational view of one of the stamped sheets of material forming the cam illustrated in the cleat of  FIG. 1   a;    
           [0031]      FIG. 3   b  is a front elevational view of the stamped sheet shown in  FIG. 3   a ; 
           [0032]      FIG. 4   a  is similar to  FIG. 3   a  of the associated or other of the stamped sheets of material forming the cam; 
           [0033]      FIG. 4   b  is similar to  FIG. 3   b  for the other stamped sheet shown in  FIG. 4   a;    
           [0034]      FIG. 5   a  is a side elevational view of the assembled cam shown in  FIG. 1   a  formed of the stamped sheets shown in  FIGS. 3   a - 4   b,  showing spot welds to secure the stamped sheets to each other; 
           [0035]      FIG. 5   b  is a front or end elevational view of the assembled cam shown in  FIG. 5   a;    
           [0036]      FIG. 5   c  is a top plan view of the cam shown in  FIGS. 5   a  and  5   b;    
           [0037]      FIG. 5   d  is a side elevational view of the cam of  FIG. 1  stamped from a single sheet of material; 
           [0038]      FIG. 5   e  is a front elevational view of the cam shown in  FIG. 5   d;    
           [0039]      FIG. 5   f  is an enlarged section of the cam shown in  FIGS. 5   d ,  5   e  and an enlarged detail of one embodiment of a surface texture of the line engaging surfaces of the cam; 
           [0040]      FIG. 6   a  is a front elevational view of a system of pulleys or sheaves including a threaded bolt and nut fastener for attaching to a ceiling or horizontal member, and showing an exploded view of the moving sheave for supporting an object, such as a potted plant, and showing an exploded view of a region D illustrating details of assembly of the movable sheave and hook arrangement; 
           [0041]      FIG. 6   b  is a side elevational view of the system of pulleys or sheaves shown in  FIG. 6   a  and showing an exploded view of region E showing the details of the hook locking plate that facilitates assembly of the movable pulley or sheave; 
           [0042]      FIG. 7   a  illustrates the details of the movable pulley or sheave of  FIG. 6   a  just prior to final assembly; 
           [0043]      FIG. 7   b  is a side elevational view of the pulley system shown in  FIG. 7   a;    
           [0044]      FIG. 8   a  illustrates another step in the assembly of the movable pulley or sheave shown in  FIGS. 6   a ,  6   b ,  7   a  and  7   b , in which the movable pulley or sheave is secured into its shield or case; 
           [0045]      FIG. 8   b  is a side elevational view of the movable pulley or sheave shown in  FIG. 8   a;    
           [0046]      FIG. 9   a  is similar to  FIG. 8   a  but illustrates the assembled movable sheave in its final state of assembly and ready for supporting an object or load on the hook supported by the movable sheave or pulley; 
           [0047]      FIG. 9   b  is a side elevational view of the movable pulley or sheave shown in  FIG. 9   a;    
           [0048]      FIG. 10   a  is an enlarged side elevational view of region F in  FIG. 9   b;    
           [0049]      FIG. 10   b  is a cross-sectional view of the hook and locking plate shown in  FIG. 10   a , taken along line  10   b - 10   b;    
           [0050]      FIG. 11  a is a front elevational view similar to  FIG. 6   a  but with a different U-shaped hook suitable for supporting a larger object such as a bicycle; 
           [0051]      FIG. 11   b  is a side elevational view of the hook and associated sheave or pulley shown in  FIG. 11   a;    
           [0052]      FIG. 12   a  is similar to  FIG. 11   a , but illustrating the hook secured within and supported by the movable sheave; 
           [0053]      FIG. 12   b  is a side elevational view of the movable sheave and associated hook shown in  FIG. 12   a;    
           [0054]      FIG. 13  is similar to  FIG. 1   a , with a modified cleat to provide multiple movable pulleys or sheaves, with associated hooks of the type shown in  FIGS. 11   a - 12   b,  for simultaneously raising and/or lowering an object such as a bicycle while maintaining the object in a generally horizontal or fixed orientation; 
           [0055]      FIG. 14  is a cross-sectional view of the modified cleat shown in  FIG. 13 , taken along line  14 - 14 ; 
           [0056]      FIG. 15  is a cross-sectional view of the stationary pulley or sheave shown in  FIG. 14 , taken the along line  15 - 15 ; 
           [0057]      FIG. 16   a  illustrates a modified, ceiling-mounted cleat for raising and/or lowering a single object with a single movable pulley or sheave; 
           [0058]      FIG. 16   b  is similar to  FIG. 16   a , but shown mounted on a vertical surface such as a wall; 
           [0059]      FIG. 17   a , partially in cross-section, illustrates a pulley or sheave assembly for lifting a single heavy object preferably with the use of a failsafe cleat of the type shown in  FIG. 1   a;    
           [0060]      FIG. 17   b  is a front elevational view, partially in cross-section, of the pulley or sheave assembly shown in  FIG. 17   a;    
           [0061]      FIG. 18   a  is a side elevational view, partially in cross-section, of a modified cleat that incorporates an alternate design for facilitating connection to a ceiling with conventional fasteners; 
           [0062]      FIG. 18   b  is a cross-sectional view of the modified cleat of  FIG. 18   a , as viewed along line  18   b - 18   b;    
           [0063]      FIG. 19  is similar to  FIG. 18   a , illustrating a wall adapter that can be used with the cleat of  FIG. 18   a  for facilitating attachment of the cleat to a vertical surface such as a wall or a vertical member; 
           [0064]      FIG. 20  is similar to the pulley or sheave assembly shown in  FIG. 1   a , but provided with a modified mounting bracket for facilitating mounting by providing adequate clearances for the fasteners and conventional tools such as a screwdriver for driving the fasteners; 
           [0065]      FIG. 21   a  is a front elevational view of a modified movable pulley or sheave construction for supporting an object by means of a flat U-shaped strap; 
           [0066]      FIG. 21   b  is a side elevational view, partially in cross-section, of the modified movable pulley or sheave shown in  FIG. 21   a;    
           [0067]      FIG. 21   c  is similar to  FIG. 21   b  showing the movable pulley or sheave ready for supporting a load, such as a potted plant; 
           [0068]      FIG. 22   a  is similar to  FIG. 21   a , but showing the use of a U-shaped support member in the form of a bent rod instead of a flat strap; 
           [0069]      FIG. 22   b  is similar to  FIG. 21   b  for the support member shown in  FIG. 22   a;    
           [0070]      FIG. 22   c  similar to  FIG. 21   c  for the support member shown in  FIG. 22   a.    
           [0071]      FIG. 23   a  is a side elevational view, in cross-section, of a cleat in accordance with the invention when used as a leech-line cleat secured to a sail; 
           [0072]      FIG. 23   b  is a front elevational view, in cross-section, of the sail-mounted cleat shown in  FIG. 23   a;    
           [0073]      FIG. 23   c  is a cross-section of the cleat shown in  FIG. 23   a , taken along line  23   c - 23   c;  and 
           [0074]      FIGS. 24   a - 24   d  illustrate the manner of contacting the cam shown in  FIGS. 23   a ,  23   b ,  23   c  from the at-rest, non-contacting condition to a leech-line locking condition. 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0075]    Referring now to the Figures, in which identical or similar parts are designated by the same reference numerals throughout, and first referring to  FIGS. 1   a - 1   c , a failsafe system for raising and/or lowering an object or a plurality of objects in accordance with the present invention, is generally designated by the reference numerals  10 . 
         [0076]    The cleated system of pulleys or sheaves  10  is configured to be conveniently mounted onto a ceiling  11  a by a consumer of average mechanical skills and with the simplest of tools, such as a screwdriver. The cleated system  10  includes a cleat  12  for locking/unlocking a control line L, as to be more fully described. 
         [0077]    The cleat  12  includes a housing  14  that is shown to be generally rectangular in shape. However, as will become evident, the specific shape of the housing  14  is not critical and generally any rectangular or other configuration suitable for the purpose, such as a square configuration, can be used. 
         [0078]    The housing  14  is formed of two clam shells  14   a,    14   b,  as best shown in  FIGS. 1   b  and  1   c . The housing  14  includes a top or upper cavity  14   c  for receiving a ceiling fastener, as to be described. The housing  14  is similarly provided with a side cavity  14   d  for receiving a wall fastener, as to be described. As shown in  FIG. 1   c  the housing is provided with a plurality of spaced, distributed closed bores  14   e  for receiving self-locking pins  15 . The pins  15  are provided with external dimensions that are slightly larger in diameter than the diameters or internal dimensions of the channels or bores  14   e  so that the pins  15  can only be received within the bores by press fit requiring slight expansion of the bores to provide adequate friction between the pins  15  and the bore internal surfaces to prevent inadvertent separation once the pins are forced into the bores. To insure a substantially permanent assembly, the pins are advantageously provided with a series of serrations  15   a - 15   c  ( FIG. 1   c  inset) that are configured or shaped as shown to allow easier entry than removal of the pins by ensuring significantly higher frictional forces for removing the pins once they are force-fit into an associated bore. When the clam shells are aligned to register each of the pins  15  with an associated pair of opposing bores opposing pressures can be applied to the shells  14   a,    14   b  to urge each of the pins into opposing associated bores when the shells  14   a,    14   b  are formed of a material that can be slightly deformed when sufficient pressures are applied, such as would be the case with Nylon or other similar plastic materials. 
         [0079]    Suitable transverse holes or apertures  14   g  are provided within each of the cavities  14   c,    14   d , for reasons to be described. 
         [0080]    Within the housing  14  there is provided a sheave or pulley wheel  16  rotatably supported on a horizontal pin  18  that bridges the two clam shells  14   a,    14   b,  a cam  20  being similarly pivotally mounted on a pivot pin  22  horizontally arranged to bridge between the two clam shells. A pusher  24 , to be more fully described in connection with  FIG. 2 , is mounted for pivotal movements about the same pin  18  that supports the sheave or pulley wheel  16 . The general construction and operation of the cam  20  has been described in U.S. Patent Application No. 61/201,817 and such application is incorporated by reference as if fully set forth herein. The aforementioned application also describes the general failsafe operation of the cleat  12  and, therefore, the details of such operation will not be fully set forth herein. 
         [0081]    Although numerous methods may be used for mounting the cleat  12  to a ceiling and/or wall, a presently preferred embodiment includes a fastener  26  that has one free end  26   a  that may have a multi-faceted cross-section such as a generally hexagonal cross-section, as best shown in  FIGS. 1   b  and  1   c . At the opposing end of the fastener  26  is a self tapping tip  26   b,  a threaded shank  26   c  being provided between the ends suitable for use with a ceiling beam or any other wooden or similar solid support member. 
         [0082]    A pin  28  embedded within the clam shells  14   a,    14   b  is parallel to the pin  18  also serves as a stop pin for the pusher  24  to hold the pusher in a predetermined rest position to maintain the line L spaced a desired distance from the cam  20 . Similarly, a pin  30 , generally parallel to the pin  22 , serves as a stop pin for the cam  20  to maintain the initial engaging portions of the cam, as to be described, a predetermined or desired distance from the line L. Thus, the pin  28  prevents excessive pivoting of the pusher  24  in a clockwise direction while the pin  30  prevents excessive pivoting of the cam  20  in a counter-clockwise direction. The pusher  24  includes two side walls  24   a,    24   b  that are pivoted on pin  18  and support a transverse wall  24   c  that, serves as a line bearing or limit stop for the line against excessive movement towards the left, as viewed in  FIG. 1 , in response to the forces applied by the advancing cam  20 . Thus, the pusher serves, with or without the stop pin  28 , as a bearing or stop surface against which the cam may press the line and wedge to arrest further movements of the line. However, as will be clear from the description of  FIGS. 23   a - 24   d  any bearing or stop surface may be used even if a fixed surface on the housing without the use of a pusher or stop pin. 
         [0083]    While the cleat  12  may, in some applications, be used alone, the system&#39;of the present invention also contemplates the use of one or more auxiliary sheave or pulley assemblies  32 . In  FIG. 1   a  only one auxiliary sheave assembly  32  is shown, although additional sheave assemblies can be mounted in tandem to allow the lifting or lowering of an object, such as a potted plant, or a plurality of objects, individually or in unison depending on the configuration of the pulleys or sheaves, as will be more fully described below. 
         [0084]    The auxiliary sheave assembly  32  includes an upper housing, frame or support bracket  34  generally having an inverted U-shaped cross-section that rotatably supports a fixed sheave or pulley wheel  36  mounted for rotation about a horizontal pin  38 . The sheave assembly  32  also includes a movable sheave wheel  40  housed within a movable shield or cover  42  and arranged for rotation about a horizontal pin  44 , which may be a straight pin or a horizontal portion of a depending hook or the like, as will be more fully described below. 
         [0085]    Referring to  FIGS. 1   a  and  6   a,  one arrangement is illustrated for assembling the auxiliary sheave assembly  32 . A C-shaped hook  46  ( FIG. 6   a ) includes a vertical portion  46   a,  an upper horizontal portion  46   b  formed with a circumferential groove  46   c  at it&#39;s free end. A circular lip or ridge  46   d  ( FIG. 6   a  inset) is provided formed with a taper or bevel  46   e  to provide a locking mechanism to be described. The lower portion  46   f  is substantially parallel to the portion  46   b  which is provided with an upwardly directed magnetized end  46   g  which is substantially vertically aligned with the groove  46   c  but slightly offset from the groove. The portions  46   a - 46   g  form a generally closed loop or hook that is only open between the free end of the portion  46   b  the portion  46   g.  To bridge that opening and form a totally closed loop there is provided an elongate generally flat locking plate  48  which, as best shown in  FIGS. 6   b ,  7   b ,  8   b  and  9   b , is provided with an elongate slot  48   a  formed at the lower end with an enlarged generally circular end  48   b  at the lower end  48   c  which is preferably formed with angled surfaces  48   d,    48   e,  as best shown in  FIGS. 10   a ,  10   b  to insure centering and retention of the locking plate  48  in relation to the portion  46   g  of the hook  46 . 
         [0086]    The assembling of the auxiliary pulley or sheave  32  will now be described in relation to  FIG. 6   a - 10   b.  In  FIG. 6   a ,  6   b  the movable sheave or pulley wheel  40  is initially placed on and supported by the line  52  as suggested by arrow  1  and arranged in a substantially vertical plane as shown in  FIG. 6   b . The sheave or pulley wheel  40  is lowered, as suggested by arrow  2 , into the shield or cover  42  to align a horizontal hole or bore  40 ′in the sheave wheel with a corresponding or associated hole  42 ′ in the shield or cover  42  so that these are aligned as shown in  FIGS. 7   a ,  7   b . As suggested by arrow  3   FIG. 7   a  the upper horizontal portion  46   b  is extended through the elongate hole  40 ′ in the sheave or pulley wheel  40  and the associated openings  42 ′ in the shield or cover  42 . As suggested by arrow  4  in  FIG. 7   a , the locking plate  48  is slipped over the taper  46   e  and the lip or ridge  46   d  so that the latter pass through the enlarged opening  48   b  to bring the locking plate  48  into alignment with the groove  46   c . The thickness of the locking plate  48  is preferably just slightly less than the width of the groove  46   c  so that the locking plate can be lowered while engaged with the free end of the horizontal portion  46   b,  as suggested in  FIG. 8   a . The length of the locking plate  48  is selected so that when it is lowered to bring the groove  46   c  to the upper end of the slot  48   a,  the lower end of the locking plate, including the angled surfaces  48   d,    48   e,  abut against the upper free end of the portion  46   g,  as shown in  FIGS. 9   a - 10   b . In a presently preferred embodiment, at least the lower end of the locking plate  48  is formed of a magnetizeable material, such as steel, and the portion  46   g  is magnetized to attract the locking plate and maintain those two elements in contact to ensure that the hook  46  is totally closed during normal use. Of course, the selection of materials and levels of magnetization will determine the magnitude of the attractive forces between the locking plate  48  and the portion  46   g.  However, such forces can be selected to allow manual separation by a user upon application of a force to the locking plate greater than the magnetic attractive forces so that the locking plate  48  can be selectively separated and moved to effectively open the hook, as suggested in  FIG. 9   b . With this construction, placement of an object on the hook  46 , such as a potted plant, ensures that the object remains attached to the auxiliary sheave assembly  32  as it is raised and lowered. 
         [0087]    Referring to  FIGS. 3   a - 5   c,  a cam construction is illustrated formed of two cam sections  20   a ,  20   b  each of which can be stamped or die-cut from flat of planar sheet material such as steel. As more fully discussed in U.S. Patent Application No. 61/201,817, which is incorporated by reference as if fully set forth herein, cam plate  20   a  includes spaced fingers, pressure pads or segments  20   c - 20   e  forming spaces or gaps  20   f - 20   h  with a first spike or gripping point  20   i.  As shown in  FIG. 3   b  the three fingers  20   c - 20   e  are deflected or bent out of the plane of the sheet material, to the left as viewed in 
         [0088]      FIG. 3   b . Similarly, cam plate  20   b  is formed with fingers  20   j - 20   k  and a second spike or gripping point  201 , forming spaces or gaps  20   m - 20   p  The fingers  20   j,    20   k  are deflected out of the plane of the sheet material forming cam plate  20   b,  to the right as viewed in  FIG. 4   b . The fingers and spaces or gaps formed between the fingers on the two plates are offset from each other so that they can mate or interlock as shown in  FIGS. 5   a - 5   c  to interleave the fingers and form a generally curved V-shaped region suitable for receiving and engaging a line. As best as shown in  FIG. 5   a  the two spikes or gripping points  20   i,    201  are slightly offset from each other. The two cam plates, once superimposed or mated as described can be secured to each other in any suitable or conventional manner such as spot welds  50  shown in  FIG. 5   a.    
         [0089]    Referring to  FIGS. 5   d - 5   f,  a further embodiment of the cam is illustrated and designated by the reference numeral  114  formed of a single sheet of material  114   a,  such by stamping. The cam  114  is formed with an opening such as a round hole  114   b  suitable for insertion of a pivot pin and is provided with a series of pressure pads  114   c,    114   d  that alternatingly angularly project substantially equal angles to opposite sides of the plane of the sheet material  114   a  as best shown in  FIG. 5   e . The deflection or offset angles from the cam plane can be any suitable amount to accommodate a given diameter of line and may preferably be within the range of 50 to 70 degrees. However, the optimal angles of deflection are 60 degrees from the cam plane to provide a total angle of 120 degrees between opposing pressure pads, simulating the internal angles of a hexagon which provide a good approximation of the cylindrical outer surface of the line. Optionally, the outwardly facing surfaces of the pressure pads  114   c,    114   d  are generally directed in a direction away from the hole  114   b  and are provided with pointed elements in the nature of spikes or barbs  114   e.  Tacky materials or any other techniques may be used instead of the spikes or barbs for better engaging or frictionally gripping the line with different degrees of advantage. 
         [0090]    The manner of securing the cleat  12  and the sheave assembly or assemblies  32  to a ceiling or to a wall will now be described. To secure these components to a ceiling the driven ends  26   a  of the fasteners  26  are inserted into the upper cavities  14   c,  the driven end  26   a  being provided with a through hole  26 ′ aligned with the hole  14   g.  A pin  27  is inserted through the hole  14   g  in the housing  14  and through the driven end  26   a  to capture the fastener  26  and secure it to the housing. With this construction, the housing to which the driven end  26   a  is secured in effect becomes a part of the fastener and can be used for driving it without the use of additional tools. After a pilot hole (not shown) is drilled in a ceiling beam  11  a the fastener  26  can be screwed into the beam by rotating the housings about the axes of the fasteners  26  until the upper surface  14   f  ( FIG. 1   b , region A) is flush or abuts against the lower surface of the ceiling, as shown in  FIG. 1   a . By rotating the housing  14  and, therefore, the fastener  26 , slightly beyond the initial point of contact between the housing and the ceiling surface the housing is drawn up against the ceiling surface and fractionally engage the same. The housing may then be rotated slightly further or back to align the housing in a desired orientation while maintaining frictional engagement to prevent inadvertent movements during use. 
         [0091]    Once the auxiliary sheave assembly  32  and the cleat  12  have been mounted on a ceiling, as shown in  FIG. 1   a , a line  52  is extended through these components. A window or opening  34 ′ may be provided to facilitate the manipulation and winding of the line about the pulley or sheave wheel  36 , as shown in  FIG. 1   b . An initial vertical portion  52   a,  attached to a storage spool  54 , is received between the cam  20  and the pusher  24 , initially making contact only with the pusher  24  with a resulting gap between the line portion  52   a  and the cam. The line is then passed over the sheave wheel  16  and a horizontal portion of the line  52   b  extends to the auxiliary sheave assembly  32  where the line passes over a first fixed a sheave wheel  36 , and then under the movable sheave wheel  40 , and then up again over a fixed sheave wheel  36  ( FIG. 6   a ) before exiting the auxiliary sheave assembly at  52   c.    
         [0092]    Advantageously, a horizontal circular channel  53   a  is positioned above the sheave  16 , the channel being open at the bottom to expose the channel  53   a  to the line portion  52   b.  A roller  53   b  is positioned within the channel  53   a  and has a diameter smaller than the diameter of the channel  53   a  so that the roller can freely rotate within the channel with clearance and so that the lowermost surface of the roller protrudes through the channel and can make contact with the line portion  52   b  as it passes over the sheave. The roller  53   b  is preferably made of a metal or other material that can exhibit sufficient weight on the flexible line to apply a downward force on the line to insure sufficient friction between the roller  53   b  and the sheave  16  to cause the sheave to rotate whenever the line advances over the sheave. This additionally insures that movement of the line also causes the rotation of the pusher  24 . 
         [0093]    In the presently preferred embodiment, the pusher  24  does not to rely on the use of springs or magnets to urge the line towards the cam  20 , as it did in the previous application Ser. No. 61/201,817. Instead, as shown in  FIG. 2 , the pusher  24  is provided with two lateral walls  24   a,    24   b  that are spaced from each other a distance substantially corresponding to the axial width of the sheave or pulley wheel  16 , a transverse line contacting bridging portion  24   d  extending between the lateral walls as shown in  FIG. 2 , a slightly deflected offset tab or friction-reducing trailing portion  24   d  extending downwardly and rearwardly from the plane of the bridging portion  24   c  as shown. The sheave or pulley wheel  16  is shown to have spaced circular surfaces on the lateral walls that are configured to be in contact with the internal surfaces of the lateral walls  24   a,    24   b  to provide at least some degree of friction there between, so that rotation of the wheel  16  imparts frictional forces to the pusher  24  that tend to rotate the pusher in the same direction as the rotation of the pulley or sheave wheel. When the line portion  52   a  is pulled downwardly, in  FIG. 1   a , by applying a tension to the line, the sheave wheel  16  rotates in a clockwise direction, aided by the roller  53   b,  urging the pusher  24  to likewise rotate in a clockwise direction, to the extent permitted by the pin  28 . However, when the line portion  52   a  is released the tension applied to the line portion  52   c  by an external load the tension in the line is reduced to zero or substantially zero and the line moves in the direction of the load, causing the sheave or pulley wheel  16  to rotate, aided by the roller  53   b,  in a counterclockwise direction, urging the pusher to likewise rotate or pivot in a counterclockwise direction and pushing the vertical line portion  52   a  of the line towards the cam  20 . This causes the spikes or gripping points  20   i  and  201  to successively engage the line and cause the cam  20  to pivot in a clockwise direction, increasingly bringing more and more of the line into contact with the fingers of the cam to wedge the line and almost instantaneously lock the line to prevent uncontrolled movements thereof. This is more fully explained in the aforementioned applications and now issued patents. 
         [0094]    When the line portion  52   a  continues to be pulled downwardly, in  FIG. 1   a , such as when raising an object attached to be auxiliary sheave assembly  32 , excessive line can be wound about the spool  54  and maintained stored on the spool by forcing a portion of the line into the L-shaped cutout  54 ′, as more fully explained in U.S. Pat. No. 6,234,454, which is incorporated by reference as if fully set forth herein. 
         [0095]    Referring to  FIGS. 11   a - 13 , a modified system is shown for lifting and lowering a bicycle or the like by providing two movable sheaves each of which it is connected to a hook so that two different spaced portions of a bicycle or other larger such objects can be engaged and simultaneously lifted to maintain the object in a substantially horizontal or other predetermined angular orientation during lifting and lowering operations. In place of the C- shaped hooks shown in  FIGS. 6   a - 10   b  bicycle hooks  62  are provided that are in the form of an inverted V, with each free end being U-shaped as shown. Once the movable sheave wheel  40  is aligned within the shield  42  one end of the hooks  62  can be passed through the aligned holes  40 ′,  42 ′ and sequential portions passes through the holes until the portion  62   c  is received within the holes as shown in  FIG. 12   a . The hooks  62 , therefore, again serve a dual purpose, namely as a pin for rotation of the wheel  40  as well as a hook for supporting an object. The operations are suggested by arrows  1  and  2  in  FIGS. 11   a ,  11   b.    
         [0096]    When only two hooks are required, such as for a bicycle, a line portion  52   d  ( FIG. 13 ) can be secured to the holding block supporting the stationary wheel such as by means of the retaining link  64  fixed to the block, frame or housing by means of a link pin  66 . The end of the line may be tied in a knot  52   e  or otherwise fixed as shown in  FIG. 15 . 
         [0097]    To provide vertical movement of a hook at the cleat housing  14  a second fixed sheave  58  is provided mounted on a pin  60  spaced from the fixed sheave the  16 , so that an additional movable sheave  32 ′ can be supported by the line forming a loop between the two fixed sheaves  16 ,  58 , as shown in  FIG. 13 . The cleat  12 ′, including the cam  20  and pusher  24  provide a failsafe mode of operation in the event that the line is released accidentally or inadvertently. It will be appreciated that when the line and the spool are pulled down both movable sheaves or pulleys will move up substantially simultaneously to raise an object. The hooks will likewise be simultaneously lowered when line is released at the spool end of the line. 
         [0098]    When a single hook is required for lifting/lowering a single object,  FIGS. 16   a - 17   b  illustrate modified constructions, for achieving that function. A retaining link  64 ′ is used, as aforementioned, to secure the end of the line at the fixed housing, frame or support structure  14 ′ attached to the ceiling  11   a,    11   b  or to a wall  11   a ′,  11   b ′ as shown in  FIG. 16   b . With the arrangement of pulleys as shown the mechanical advantage is two so that a user needs only apply one half of the force corresponding to the weight of the article or object being lifted. A similar construction is shown in  FIGS. 17   a ,  17   b  for an auxiliary sheave assembly in which a depending bracket  70  having upper ends secured to a pin  38  and a washer  72  being provided with a hole  74  through which the end of the line  52   g  may extend and be terminated in a knot  52   h.  The bracket is used in place of a connecting link. By using two pulley wheels  36 ′,  36 ″ on top as fixed wheels and two movable wheels  40 ′,  40 ″ within the casing or shield  42 ′a mechanical advantage of four may be achieved. 
         [0099]    In an effort to simplify mounting of both the cleat as well as the auxiliary sheave assemblies,  FIGS. 18   a - 20  show mounting holes with counter sinks  76  located in positions to facilitate insertion of a screw  78  with a screwdriver in a convenient manner. This construction provides clearances  80   a ,  80   b  (dimensions Δ1, Δ2, respectively) for the screwdriver and screws at  80   a,    80   b,  and  82   c  in  FIG. 20 . For mounting on a wall, a wall adapter  84  is used that cooperates with a recess  86  ( FIG. 18   a ) in the cleat housing and has a locking ridge or lip  88  ( FIG. 19 ) dimensioned to mate within the recess, a snap fastener  90  being receivable within the mounting holes  76 , shown in  FIG. 19 . Thus, the wall adapter  84  can be attached to a wall or vertical support member in a convenient manner. The cleat may be secured to the adapter by snapping it in place by initially inserting the snap fastener  90  through the hole  76  and urging the locking lip  88  to snap into the recess  86 . These designs facilitate mounting both cleats and auxiliary pulleys or sheaves by almost any user by using a simple screwdriver. 
         [0100]      FIGS. 21   a - 22   c  illustrate additional constructions of movable sheaves that use conventional pins or rivets to secure the wheels to the associated shields or covers, with U-shaped hooks supported on the pivot pins or rivets in any conventional manner. Holes  42   c  are provided at the lower regions of the shields or covers  42  to provide a means for water to escape or be removed from the shields or covers when these are used outdoors and rainwater may otherwise accumulate therein. The assemblies described herein may be used indoors or outdoors to accommodate decorative as well as environmental conditions. 
         [0101]    Preferably all of the embodiments that have been described provide the holes  42   c  at the bottoms of the covers or shields  42  to insure that no water accumulates therein, whether used indoors or outdoors, as shown in  FIGS. 21   a - 22   c.  In  FIGS. 21   a - 21   c  the hook  96  is suspended on the same pin  44  that also supports the sheave  40  and is formed of a bent flat strip of material such as steel or aluminum. Each end of the hook  96  is formed with the slots and holes detailed in  FIGS. 6   a - 6   b  to facilitate mounting of the hook on the pin. In  FIGS. 22   a - 22   c  a similar construction is shown in which the bent strip  96  is replaced with a bent rod  98  with flattened ends as shown and secured by a rivet that also serves as a pivot pin for the sheave  40 . 
         [0102]    One further application of the cams  20 ,  114  is shown in  FIGS. 23   a - 23   b,  where the housing  112  of the cleat  110  and a plate  152  are secured by means of rivets  142 ,  144  to a trailing edge of a sail  145  of a sailboat. Such cleat  110  is commonly referred to as a leech-line cleat for controlling the line  138  (“leech line”). 
         [0103]    The cavity  112   a  is dimensioned and configured to movably receive a cam  114 . The housing  112  is provided with openings  112   b,    112   c  ( FIG. 23   b ) for receiving transverse pins  118  that extend through the cavity  112   a.  The openings  112   b,    112   c  may be provided with bevels on the exterior surface of the housing as shown for receiving tapered heads of the pins. An opening  112   d  is provided adjacent to the cavity  112   a  as shown for receiving magnet(s)  136  for attracting the cam  114  towards the magnets and away from the line  138 , a function that is desirable in an unstable environment such as on a sailboat. In other, stable environments where the cleats are attached to fixed support surfaces reliance may be had on gravity to drop the cam to increase the spacing from the line. 
         [0104]    Referring to  FIG. 23   c , each line cleat  110  of  FIGS. 23   a ,  23   b  is shown in the assembled state and in cross-section to illustrate the generally V-shaped cross-section forming the line receiving region of the cam  114 . However, the cross-section may also assume other cross-sections suitable for receiving a line, such as U-shaped, semi-circular, etc. that can contact a significant circumferential surface of the line. The cavity  112   a  includes spaced parallel surfaces  112   k,    1121  ( FIG. 23   b ) that form a narrow region  112   m  in the form of a narrow gap having a width T g  ( FIG. 23   c ) slightly greater than the thickness “t c ” of the flat portion  114   a  to receive the flat portion with some clearance to allow the flat portion to freely move within the gap or narrow region  112   m  when the cam  114  pivots about the pin  118 . The rest of the cavity  112   a  beyond the gap or narrow region  112   m  has a thickness “T” that essentially corresponds to the diameter “d” of the line  138  to receive the line with clearance preferably without compressing the line or creating friction as the line moves through the cavity  112   a  along direction M. The maximum transverse dimension “t” ( FIG. 23   c ) of the offset pads or segments  114   c,    114   d  is slightly less than the width “T” of the cavity so that the cam pads or segments can move freely within the cavity as the cam pivots about the pin  18 . 
         [0105]    The line  38  is normally spaced a distance Δ ( FIG. 23   c ) from the inclined pressure pads  114   c ,  114   d,  providing a safe margin of clearance that normally prevents the line  138  from engaging the cam  114 . As a further measure to prevent such undesired inadvertent or premature contact of the line  138  with the cam  114  the line is preferably maintained slightly deflected from the vertical by an angle Θ° greater than 0° ( FIG. 23   a ). Even an angle Θ of 1° or 2° is sufficient, although greater angles can be used. Similarly, the housing  112  may be mounted so that the load force F L  is slightly offset an angle φ off the vertical in a direction away from the position of the cam  14  to promote contact with the housing and separation from the cam. 
         [0106]    The lower end of the leech line  138  is accessible to the user. However, the upper end of the line extends into a channel  146   b  of a sleeve or pocket  146   a  formed by a folded strip  146  of material sewn to the sail along stitch lines  146   c,    146   d  after passing through the cleat  110 . A line  150  may secure the lower corner of the sail by means of a eyelet  148 . To prevent excessive friction the housing is preferably provided with rounded edges  12   r  at the leading and trailing ends of the line-receiving channel in the cleat cavity. 
         [0107]    As with the cleat  110 , the line  38  is preferably maintained inclined at an angle to avoid premature contact of the line with the cam. In  FIG. 23   a  the angle Θ may be comparable to the angle Θ, although this angle may be somewhat less since there is no pusher force to overcome. Referring to  FIGS. 24   a - 24   d  the sequence of, positions of the cleat  110  is shown to arrest or lock the movements a leech line. Initially, the leech line is manually moved in the direction M L . While the degree of movement M L  is not critical any movement is adequate that causes contact between the line and the cam. The cam  110  progressively and increasingly compressed the line and when the friction forces rise to a sufficient level they are adequate to stop the leech line, as represented by the force F F . 
         [0108]    The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.