Abstract:
A portable hoist adapted for attachment to a hand truck nose plate is disclosed. The hoist comprises an adapter that sandwiches the nose plate and a hole or holes may be fabricated in the nose plate for securing hardware to be installed, such as a bolt, bolts, strap, etc. Receivers on the hoist hold removable, load supportive legs securely in place. Casters may be attached to legs to improve mobility. A jib assembly capable of several height settings remains reasonably level at all times when in use, making it ideal for tight spaces. The pivot point of the arm is at the end of the mast opposite the adapter assembly, the other end attaching to the handle of the hand truck and securing with a latch. A winch attached to the arm provides a cable extending to and about a sheave or sheaves, terminating beyond the sheave carried at the free end of the jib boom. A brace on the mast allows the arm latch to secure when the arm is collapsed. The jib assembly folds downward with a brake to hold the boom reasonably parallel to the mast. A cable securing hook is attached to the mast, and with slight tension on the cable, the latch brace and cable hook enable the hoist to be carried about easily, utilizing the boom as a handle.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to hoists, specifically to portable and mobile hoists. While many hoists available may accomplish the same task of article manipulation, they all include features which limit the scope of their use. For instance, some are designed to be anchored to a floor, wall or land vehicle. Others are very heavy and bulky, making them a less likely candidate to be used on flat commercial rooftops or in poorly accessible work areas. These limitations force many well designed hoists to be dismissed simply as the wrong tool for the job in situations where the work they accomplish is in demand. 
     For example, in the commercial HVAC service industry, technicians frequently replace refrigeration compressors and electric fan motors weighing in excess of two hundred pounds. Often, the units containing them are located upon flat rooftops, so an extension ladder, rope and a common hand truck are utilized to get the job done. If the compressor or fan motor is too heavy to safely lift, additional personnel or expensive crane rentals become the only safe and viable alternatives. 
     Typically, extension ladder hoists are be used to raise a load from the ground surface at the bottom of the ladder to the rooftop. A common hand truck is then used to transport the motor laterally across the roof surface to the air conditioner or air handling unit. However, once the technician arrives at the unit to be repaired, the load must be manually lifted and placed into its compartment, as well as getting the existing load out and carefully setting it down on the roof surface. These compartments are typically one to three feet above the roof surface, creating an unsafe lifting practice, often resulting in injury or property damage. Hence, a mechanical advantage for this and many other similar scenarios is greatly needed. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  shows the hoist attached to a hand truck in the upright operational position. 
         FIG. 2  shows the hoist in the collapsed position with the legs detached. 
         FIG. 3  shows the hoist arm in an alternative position, illustrating both the pivotal and telescopic characteristics necessary for collapsing as well as adapting to hand truck frames of various dimensions. 
         FIG. 4  shows the jib assembly secured to the mast in the operational position. 
         FIG. 5  shows a perspective view of the positions of sheaves  1  and  2  as well as the cable routing through the upper end of the mast and the jib assembly. 
         FIG. 6  shows a perspective view of the position of sheave  3  as well as the cable routing at the free end of the boom. 
         FIG. 7  shows the adapter assembly and the inserted as well as removed positions of the legs into and from their respective receivers. 
         FIG. 8  shows an alternative embodiment design of the jib assembly, employing a trolley style bracket with caged roller bearings and no sheaves. 
         FIG. 9  shows an alternative embodiment design of the adapter assembly and legs. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     An adapter assembly  10 , shown in  FIGS. 1-4  and  7 , is made of rigid, forged, and/or extruded parts attached to one another at desirable contact points. Assembly  10  is comprised of: adapter plates  12 A,B; an adapter plate bridge  14 ; an adapter angle brace  16 ; three leg receivers  20 L,C,R. 
     Adapter plates  12 A,B, shown in  FIGS. 1-4  and  7 , are made of flat, rigid material of a predetermined size, shape, and thickness. The two plates maintain sufficient parallel positioning with respect to each other as they are bridged together by adapter plate bridge  14  made of a long, narrow segment of flat, rigid material of adequate size, length, shape and thickness. 
     Adapter brace  16 , made of a segment of angle iron, angle brace material, or the like, is attached flatly against plate  12 A upon the surface which faces away from plate  12 B, while remaining parallel to the lengthwise dimension of bridge  14 . In the preferred embodiment, the exposed outside surface of brace  16  faces bridge  14  when attached to plate  12 A. 
     As is shown in  FIG. 7 , leg receivers  20 L,C,R are made of rigid, C-shaped channel material of a desired size, length, and thickness, and are attached to the outside surface of brace  16  that is perpendicular to plate  12 A and facing bridge  14 . A leg receiver hole or holes  22  formed in receivers  20 L,C,R, should be of adequate diameter and position so as to allow passage of a leg securing pin  28 , such as a detent pin, a clevis pin, or the like. 
     An adapter mounting hole or holes  18 , also shown in  FIG. 7 , are formed in plates  12 A,B and brace  16 . The holes should be of sufficient diameter, alignment, and position so as to allow passage of a preferred fastener or fasteners, such as a mast strap  40 , comprising a U-shaped bolt or bolts, as is illustrated in  FIG. 2 . 
     Legs  24 L,C,R, illustrated in  FIGS. 1 and 7 , are made of rigid, elongated tubing or the like of a predetermined size, length, shape, and thickness, and should have dimensional characteristics at one end so as to permit insertion into corresponding leg receivers  20 L,C,R, with reasonable ease. In addition, the gaps between the receiver inside surfaces and the leg outside surfaces should be kept as minimal as possible. A leg securing hole or holes  26  are formed in one end of each leg, aligning with corresponding holes  22  when inserted into corresponding receivers  20 L,C,R. Holes  26  must be of adequate diameter so as to allow passage of a leg securing pin  28 , such as a detent pin, clevis pin or the like. 
     At the ends of legs  24 L,C,R opposite holes  26 , a caster mounting plate  30  is attached to each leg in a fashion so as to position plate  30  sufficiently level when the apparatus is in the operational upright position, as is shown in  FIG. 1 . The caster mounting plate is made of flat, rigid material of a desired size, shape, and thickness, and having caster plate holes  32 , slots, or the like formed in such a pattern so as to correspond to standard caster mounting plate configurations. A caster  36  is secured to plate  30  by caster mounting bolts  34  and their respective hardware. 
     A mast  38 , illustrated in  FIGS. 1-5 ,  8  and  9 , is made of rigid, elongated tubing, I-beam or the like of a predetermined size, length, shape, and thickness. It is attached along one end to plate  12 B, being positioned flatly upon and centered within the plate surface, as well as parallel to the plate outside edges that are adjacent to bridge  14 . Mast  38 , where attached to plate  12 B, should be correctively angled by bending, cutting, etc., to compensate for its respective plate angle, if necessary. This ramification should result in mast  38  being reasonably perpendicular to the working surface when the apparatus is in its operational upright position. 
     A latch securing brace  42 , shown in  FIGS. 1-4 , comprises a C-shaped rigid material, and is attached to mast  38  upon the surface opposite the leg receivers  20 L,C,R, with the base length of the brace positioned parallel to bridge  14 . Brace  42  should have the legs of its C-shaped design attached to the mast surface at their endmost points, positioning them perpendicularly to their respective mating surface. 
     As illustrated in  FIGS. 1-4 , a cable securing hook  44 , made of a rigid material of a desired size and shape, such as L-shaped, curved, etc., is attached to mast  38  upon the surface opposite brace  42 . Hook  44  is positioned with reasonable perpendicularity with respect to the mating surface, so as to permit a cable terminal  110 , shown in  FIG. 1 , to be placed about as well as removed from hook  44  with reasonable ease. 
     A plurality of jib height adjustment holes  46 , illustrated in  FIGS. 1-5  and  8 , is formed along the surfaces of the mast adjacent to brace  42 . Holes  46  are to be of a predetermined diameter, position, and quantity. They should align sufficiently with the corresponding holes of their opposing surface so as to permit passage of a jib bracket lock-pin  66 , such as a wire locking-pin or the like. 
     Two arm pivot braces  56 , as shown in  FIGS. 1-5 , are made of flat, rigid material of a desired size, shape, and thickness, and are attached to mast  38  upon the surface common to brace  42 . Braces  56  are positioned perpendicularly with respect to their mating surface, and sufficiently parallel with respect to each other. Braces  56  include a hole formed in each, having a sufficient diameter and being positioned in alignment with one another so as to adequately permit passage of an arm pivot pin  92 , such as a clevis pin or the like, simultaneously. 
     A mast cable slot  54 , as is illustrated in  FIG. 5 , is formed in the mast surface common to braces  56 , and is positioned between braces  56  and the end of mast  38  opposite assembly  10 . Slot  54  should be of adequate dimensions so as to allow the unrestricted passage of a cable  108 , also shown in  FIG. 5 . 
     Upon the surface of mast  38  opposite of and in alignment with slot  54 , a sheave# 1  slot  50  is formed, as is illustrated in  FIGS. 1 and 5 . Slot  50  must be of adequate dimensions so as to permit passage of a sheave# 1   48 , which should be recessed within mast  38 , and having a desired portion of its mass protruding outside of slot  50 . A hole of a predetermined diameter and position is formed in each mast surface adjacent to slot  50 . The two holes should align sufficiently, so as to permit passage of a sheave# 1  pin  52 , such as a clevis pin or the like, simultaneously. Once sheave  48  bore is positioned between the two holes, pin  52  is inserted, forming an axle about which sheave  48  may rotate. 
     A jib assembly  58 , shown in  FIGS. 1 ,  2 ,  4  and  5 , is comprised of: a jib mounting bracket  60 ; a boom  68 ; two sheave# 2  braces  80 ; a boom support  84 ; a jib pivot brake  86 . 
     Bracket  60 , as is illustrated in  FIGS. 1-5 , is made of a segment of rigid, C-shaped channel material of a predetermined size, length, and thickness. A portion of the channel material&#39;s base is removed from one end, resulting in the length of the legs of the channel material being longer than that of the base at this altered end. 
     Two jib bracket slots  62 , shown in  FIGS. 1-5 , are formed in the sections of the bracket legs which extend beyond the base of the channel piece. Slots  62  should be of adequate diameter and alignment with respect to each other so as to allow passage of pin  66 . Slots  62  should be of sufficient length so as to accommodate the pivoting of assembly  58  when attached to mast  38  with pin  66 . 
     As shown in  FIG. 2 , at the ends of the legs of bracket  60  opposite slots  62 , two jib bracket holes  64  are formed. Holes  64  must be of adequate diameter and alignment with respect to each other so as to allow passage of pin  66 . 
     As is illustrated in  FIGS. 1 ,  2 , and  4 - 6 , boom  68  is made of a segment of rigid, elongated tubing, I-beam, or the like, of a desired size, length, shape, and thickness. It is attached at one end to the outside base surface of bracket  60 , toward the end with holes  64 . At the other end of boom  68 , a boom cable slot  76 , shown in  FIG. 6 , is formed in the surface facing the altered end of bracket  60  base. Slot  76  should be formed of adequate dimensions so as to allow the unrestricted passage of cable  108 . 
     Upon the surface of boom  68  opposite of and in adequate alignment with cable slot  76 , a sheave# 3  slot  72  is formed, as illustrated in  FIG. 6 . Slot  72  must be of adequate dimensions so as to permit the passage of a sheave# 3   70 , which is to be recessed within the boom, and having a desired portion of its mass protruding outside of sheave slot  72 . A hole of predetermined diameter and position is formed in each boom surface adjacent to sheave slot  72 . The two holes must align sufficiently, so as to permit passage of a sheave# 3  pin  74 , such as a clevis pin or the like, simultaneously. Once sheave  70  bore is positioned between the two holes, pin  74  is inserted, forming an axle about which sheave  70  may rotate. 
     Braces  80 , shown in  FIGS. 1 ,  2 ,  4 , and  5 , are made of flat, rigid material of a predetermined size, shape, and thickness, and are attached to both boom  68  and bracket  60 . They are positioned perpendicularly with respect to their mating surfaces, and sufficiently parallel with respect to each other. The spacing of braces  80  must adequately permit the insertion of a sheave# 2   78  between them. A hole formed in each of braces  80  of a predetermined diameter and position are to be aligned with respect to each other so as to allow passage of a sheave# 2  pin  82 , such as a clevis pin or the like, simultaneously. Once sheave  78  bore is positioned between the two holes, pin  82  is inserted, forming an axle about which sheave  78  may rotate. 
     Support  84 , illustrated in  FIGS. 1-5 , is made of a segment of rigid, elongated tubing, I-beam, or the like, of a predetermined size, length, shape, and thickness. It is attached at one end to the surface of bracket  60  that is common to boom  68 , and in close proximity to the altered edge of the bracket base. It should be positioned at an angle so as to aim toward the intended support point along the span of boom  68 . Support  84  has angled ends so as to achieve a maximum surface area of contact along bracket  60  as well as along boom  68 . 
     The jib pivot brake  86 , shown in  FIGS. 1-5 , is made of a flat, rigid material of a predetermined size, shape, and thickness. Brake  86  is attached to support  84 , perpendicularly with respect to its mating surface, which should be facing slot  76 . In the preferred embodiment, brake  86  should have an outside edge parallel to the lengthwise dimension of boom  68 . 
     As is illustrated in  FIGS. 1-5 , a male arm piece  88 , made of a segment of rigid, elongated tubing or the like of a predetermined size, length, shape, and thickness, includes two or more holes of a desired diameter formed at one end. The holes should be located opposite each other and positioned so as to sufficiently align with the holes in braces  56 , when the arm piece is inserted between them. Arm piece  88  is attached to braces  56  by inserting a pivot pin  92 , such as a clevis pin or the like, through both braces  56  and the holes in the end of arm piece  88 , simultaneously. A plurality of arm length adjustment holes  90  of a predetermined diameter, position, and quantity, are formed along two opposing sides of arm piece  88  and should have sufficient alignment with respect to one another so as to permit passage of an arm length adjustment pin  96 , such as a detent pin or the like, simultaneously. 
     As is shown in  FIGS. 1-3 , a female arm piece  94  is made of a segment of rigid, elongated tubing, or the like, of a predetermined size, length, shape, and thickness. In the preferred embodiment, the inside dimensions of arm piece  94  should be greater than the outside dimensions of arm piece  88 , so as to allow a telescopic feature when placed about arm piece  88 . Two or more holes of a predetermined diameter and position are formed in opposing sides of arm piece  94 . These holes should align with their corresponding holes  90  once arm piece  94  is at the desired position about arm piece  88 . Arm piece  94  is attached to arm piece  88  by inserting pin  96  through both arm pieces simultaneously, while they are in a telescopic position in relation to one another. 
     A latch  98 , illustrated in  FIGS. 1-3 , is made of a flat, rigid material of a predetermined size, shape, and thickness. It is attached to one end of arm piece  94 , so as to cradle the handle of a hand truck  100 , shown in  FIG. 1 , when the attached arm piece slides in a telescopic motion about arm piece  88 , toward braces  56 . 
     As is shown in  FIG. 1 , a winch  102  is mounted to arm piece  94  and positioned so as to feed and retrieve its cable or the like toward or from sheave  48 . The winch may be permanently attached to arm piece  94  or fastened to it with common winch mounting hardware. For example, a winch mounting bolt  104  and a winch mounting strap  106 , or U-bolt, may be employed. 
     Also in  FIG. 1 , cable  108  is shown to be routed from the reel of winch  102  through slot  54 , about sheave  48 , through slot  50 , between sheave  78  and bracket  60 , about sheave  78 , about sheave  70 , through slot  72  and finally through slot  76 . A teardrop shape or its equivalent is typically formed at the end of the cable by installing common rigging hardware, such as a cable terminal  110  and a grab hook  112 . 
     In operation of this invention, a hole or holes should first be formed in the nose plate of truck  100  in alignment with holes  18 , if adapter assembly  10 , when properly mounted, has holes  18  positioned anywhere within the nose plate surface area of truck  100 . 
     The frame of truck  100  is then placed horizontally on the working surface, with the nose plate aiming in an upward direction. 
     With the invention in the collapsed and upright position, as is illustrated in  FIG. 2 , hook  44  and brake  86  secure the apparatus to one side of mast  38 , while winch  102  and brace  42  secure it on the opposite side, via cable  108 . In this position, assembly  10  is then placed upon the nose plate of truck  100 , sandwiching it between plate  12 A and plate  12 B. At this point, the apparatus is resting its weight entirely upon the nose plate of truck  100 , by bridge  14  engaging the topmost outside edge of the nose plate of truck  100 . Holes  18  should then be aligned with the corresponding preformed nose plate holes, if applicable. Strap  40  or the like is then inserted through holes  18  and the nose plate holes, simultaneously. Strap  40  should then be secured with the preferred respective hardware, such as nuts, washers, etc. 
     Pin  96  is then removed from arm piece  94 . Winch  102 , secured to arm piece  94  with bolt  104  and strap  106 , is then operated so as to feed cable  108  toward sheave  48 , thus lowering arm piece  94 , as well as preventing it from moving to an undesirable position. This telescoping motion disengages latch  98  from brace  42 . At this point, arm piece  88  should be pivoted outward and upward, away from adapter assembly  10 , rotating about pin  92 , which is secured to braces  56 . The resulting position is shown in  FIG. 3 . 
     An additional length of cable  108  is then fed from winch  102  as necessary, so as to allow arm piece  94  to move to a position whereas latch  98  can cradle the handle of truck  100  with reasonable ease. Once latch  98  is in the desired position, cable  108  is retrieved toward winch  102  until latch  98  engages the handle of truck  100 . Pin  96  is then reinserted through both arm pieces, as the alignment of the nearest holes  90  dictates, resulting in the position illustrated in  FIG. 1 . 
     With adequate slack in cable  108 , terminal  110  is then disengaged from hook  44  by grasping it and pulling it in a downward and outward motion, away from mast  38 . 
     Once terminal  110  is disengaged from hook  44 , and with slots  62  bearing pin  66 , assembly  58  is pivoted upward and outward away from adapter assembly  10 . This pivoting motion is created by bracket  60  rotating about pin  66 , which is secured to mast  38  through slots  62  and holes  46 . This motion ceases when the inside base surface of bracket  60  engages the surface of mast  38  that is facing bracket  60 , or when holes  64  sufficiently align with holes  46 . The second pin  66  should then be installed at the top of bracket  60  to secure it, if at the desired height. This resulting position is shown in  FIGS. 1 ,  4  and  5 . 
     However, if another jib height setting is desired, pin  66  that secures assembly  58  may be removed and assembly  58  slid up or down the mast, until slots  62  and holes  64  align with their respective holes  46 . Bracket  60  can then be secured to mast  38  with pins  66 . 
     Legs  24 L,C,R are then inserted into their corresponding leg receivers  20 L,C,R, and rested upon brace  16 , as is shown in  FIGS. 1 and 7 . Once holes  22  align with holes  26 , pins  28  should be inserted. 
     If casters  36  are not already attached to plates  30 , they should be attached by inserting bolts  34  through holes  32  as well as through the corresponding factory supplied mounting holes in the caster brackets. The recommended respective hardware, such as nuts, washers, etc., is then fastened, securing the casters to plates  30 . 
     Truck  100  is then lifted by grasping its handle and pulling the frame upward, so as to rotate it about its axial components until casters  36  engage the working surface. By holding the handle of truck  100  with both hands and manually pushing and/or pulling it while walking behind it, the apparatus is transported to the desired working area. 
     Once terminal  110  is in the desired proximity of the load that is to be lifted, a grappling device such as hook  112  may be attached, as shown in  FIG. 1 . Hook  112  or the like should then be attached to the load or its respective rigging, feeding or retrieving cable  108 , if necessary, by operating winch  102  as the situation necessitates. 
     When cable  108  is safely secured to the load, the operator holds the handle of truck  100  firmly with one hand while operating winch  102  using the free hand, so as to retrieve the cable toward the winch reel until the load is elevated, disengaging its supportive surface or structure. While raising the load, cable  108  travels along the groove surfaces of sheave  48 , sheave  78 , and sheave  70 , via slot  50 , slot  72 , slot  54  and slot  76 , simultaneously. Sheave  48  rotates freely about pin  52 , which is secured to mast  38 . Sheave  78  rotates freely about pin  82 , which is secured to braces  80 . Sheave  70  rotates freely about pin  74 , which is secured to boom  68 . Once the load is suspended, boom  68  and boom support  84  bear much of the load stress, as do adapter plates  12 A and  12 B. 
     Holding the handle of truck  100  with both hands, the operator may then transport the load to the desired work area by manually pushing and/or pulling the apparatus while walking behind it, eventually centering the suspended load directly above the surface or structure of intended engagement. When the transporting motion ceases, the operator releases one hand from the handle and uses this free hand to operate the winch, so as to feed the cable toward sheave  48 , while firmly holding the truck handle with the other hand. 
     Once the load safely engages the desired surface or structure to the point that sufficient slack is in cable  108 , the rigging means may be disengaged and the grappling device removed. Collapsing and securing of the apparatus is the opposite of set-up. 
     ALTERNATIVE EMBODIMENTS 
     In an alternative embodiment, assembly  10  may also be fabricated as a single casting, with sockets to hold the respective components, such as a mast  38  and legs  24 L,C,R. 
     Plates  12 A,B and bridge  14  may be replaced by a single longer plate that is fashioned so as to form the necessary U-shape. 
     Additionally, adjustable leg components may be used to better adapt to the wide array of available hand trucks. For instance, as is illustrated in  FIG. 9 , leg pivot brackets  120  may replace receivers  20 , providing a pivoting leg adjustment feature by using leg pivot pins  122 , leg pivot lock-pins  124 , and a plurality of leg pivot adjustment holes  120 ′. Brace  16  may be positioned however necessary to accommodate this feature. 
     The legs themselves may be made of a female leg piece  126  and a male leg piece  128  which, when combined, provide a telescopic feature so as to allow for custom leg length adjustments. A plurality of leg length adjustment holes  130  should be formed in one of the pieces, allowing a leg length lock-pin  132  to be inserted through preformed holes in leg piece  126  and holes  130 , so as to secure the leg at the desired length. 
     A caster post  134  may be perpendicularly attached to plates  30 , having a plurality of caster post adjustment holes  136 . Post  134  should pass through the bottom and top surfaces of leg piece 128 , providing height adjustment by aligning holes  136  with preformed holes in leg piece  128 , and inserting a caster post lock-pin  138 , so as to secure the post at the desired height. 
     As with assembly  10 , assembly  58  may be fabricated of a single casting with a socket or sockets to accommodate respective components, such as boom  68  as well as sheave  78 . As shown in  FIG. 8 , it may also comprise caged roller bearings  116  or the like, creating a jib trolley  114  embodiment, allowing a vertical movement of the assembly up and down the mast, with cable  108  attached by employing a bolt shackle  118  or the like. 
     All telescoping parts may also be designed so as to reverse the male and female roles, such as arm piece  88  with arm piece 94 , and leg piece  126  with leg piece  128 . 
     In order to accommodate P-handle style hand trucks, latch  98  may be designed accordingly, so as to straddle the P-handle by implementing a split-latch tandem feature to maintain a centered arm piece  94 , when the latch is fully engaged. 
     CONCLUSION, RAMIFICATIONS AND SCOPE 
     Accordingly, the reader will see that this invention can be easily transported to rooftops and navigate tight areas such as pump rooms and mechanical equipment rooms quickly and diligently. It has several advantages over hoists currently available in that
         it is light weight and easy to carry;   it can be collapsed and stored on a service vehicle without crowding the vehicle;   it permits one person on a rooftop to quickly perform the work of two people and;   it provides a low profile cable design and level boom with several height settings, making it capable of surgically removing heavy items from tight compartments.       

     Although the above description contains many specifics, these should not be construed as the sole scope of the invention. As is shown in the illustrations, for example, several other shapes, structural embodiments and materials may be used. A trolley style jib assembly with caged roller bearings can replace the fixed style jib; extendable pivoting legs with adjustable height casters may be employed; cast parts can replace assemblies, etc. 
     Thus the full scope of the invention should be determined by the appended claims, rather than merely the examples given.