A mechanical trolley with enhanced stair climbing capabilities

Abstract

A dolly has a frame having a first end and a second end, a handle adjacent the first end, and a platform extending from the second end. A wheel adjacent the second end supports the frame and platform for rotational movement. A lever member having a first end is pivotally connected to the frame at the first end and the second free end. A position stabilizing member is pivotally connected to each side of the frame proximate the second end, with each shoe assembly pivoting to a support position extending below a respective wheel. The free end of the lever member is positioned against a surface, and movement of a shoe portion of each shoe assembly to the support position causes the frame to pivot thereabout. An automatic braking system prevents unwanted downward movement. The repositioned lever member and multiple commonly hinged lever members allow for complete stair climbing and elimination of the position stabilizing member.

Description

Detailed Description of the Invention

[0001] [Technical field] This application benefits from provisional patent application serial numbers 63 / 298952, 63 / 322709, and 63 / 330795, filed on January 12, 2022, March 23, 2022, and April 14, 2022, respectively, the disclosures of which are incorporated herein by reference in their entireties.

[0002] The present invention relates to a mechanical trolley with enhanced stair climbing and descending capabilities, which is particularly effective when used with heavy loads.

[0003] [Background technology] Trucks described as "stair climbing" are well known in the art. In many instances, stair climbing trucks rely on a rail-like member located behind the main set of wheels that allows the truck to be pulled and / or slid over the end of a stair step until wheel engagement occurs on the next flat surface or stair. Examples of this type of stair climbing truck can be found in U.S. Pat. No. 4,046,391 to Restad et al., U.S. Pat. No. 4,570,953 to McPeak et al., and U.S. Pat. No. 4,962,992 to Cuschera.

[0004] While improvements over the conventional prior art, these disclosed improvements still require significant effort from the person using the dolly in that the majority of the weight of the load must be carried by the person at certain points in the journey up and / or down stairs when the primary wheels are not on a horizontal surface. Others have attempted to overcome this problem by using motorized or electric features. However, adding motorized or electric features to a dolly significantly increases the cost of the dolly and also makes the dolly dependent on the availability and cost of consumables such as fuel, batteries or other power sources.

[0005] Summary of the Invention It is therefore an object of the present invention to provide an improved trolley structure having advantageous readily available mechanical features that can be engaged or disengaged as required to assist an operator in lifting or lowering a load on stairs or in conventional trolley operation on flat or inclined surfaces without the use of motorized or electrical functions, thereby extending conventional trolley technology so that it can be more easily used on stairs.

[0006] In general, the present invention comprises a mechanical method and apparatus for enhancing the ability of a wheeled dolly to move large capacity heavy loads, which may be controllably moved, particularly up and down stairs, by utilizing one or more lever elements in a series of related manipulated positioning, or in embodiments having a combination of length adjustable lever elements and intermediate weight supports, or in embodiments having height position stabilization devices, while minimizing manual weight manipulation and devices to effect such movement. An automatically controlled braking system stabilizes the dolly both up and down stairs, minimizing unwanted motion, providing additional control and minimizing effort. Although the dolly device operates with mechanical load transport, it is understood that the control devices used to effect the operation of the present invention include both mechanical and electrical actuation.

[0007] This method consists of the following steps: a) providing a prior art dolly with a mechanism at the rear of the frame configured to be repeatedly affected by a shift in the center of gravity of the load on the dolly (in various embodiments, the mechanism is hinged at or near the top or at or near the middle of the frame); The mechanism facilitates lifting of the dolly by moving the dolly rearwardly when pressure of an applied weight resulting from a center of gravity shift occurs rearwardly toward the handle. One embodiment of the mechanism affected by center of gravity shift comprises at least one integrally hinged elongated lever member having a free end configured to be moved rearward (relative to a carried load) and engaged with a higher, typically planar surface, such as a stair step, to provide a lever lift associated with the center of gravity shift; b) depending on the positioning, extent of lever lift, and number of lever elements as described below, the dolly may further optionally comprise an engageable and disengageable intermediate weight support or position stabilizer (particularly where the lever lift is in increments less than the stair rise height) which is deployable after the initial lever lift to allow the integrally hinged lever member to be disengaged to extend without moving downwardly to provide successive additional lever lifts for stair or step clearance; and c) In particular for controllable lowering operations and for stabilized lifting, the carriage is provided with an engageable and disengageable braking arrangement (preferably automatically actuated) configured to retard downward or rearward movement of the carriage and to control downward movement during the upward movement of the carriage for stabilization.

[0008] In general, use of the dolly as configured in the first embodiment for moving a load up a step of a staircase is effected by the following steps: moving the wheels of the dolly over a surface or flat area adjacent to a first step of a staircase and proximate to the rise of the first step (or alternatively, bringing the dolly adjacent to the first step); i. a mechanism influenced by center of gravity shift, such as an integrally hinged elongated lever member extending away from the inclined carriage and bringing the free end into supporting engagement with a second, higher step, and using the lever member as a lever to lift the load against the rise of the first step; ii. deploying (automatically or manually) a load support structure to hold the load in place while the lever member is extended, providing a lever lifting capability; iii. levering the dolly out of its load-bearing holding location using the extended lever member so that the wheels of the dolly can move further upwardly and onto the second staircase step; iv. voluntarily (or manually) releasing the load-bearing structure and returning the lever member to its original length; and v. Steps ii through iv are repeated until the trolley has cleared the top floor stairs and exited onto the landing, the braking structure preventing unwanted backward movement during ascending or descending travel up and down the stairs.

[0009] In at least one embodiment of a dolly device, the invention provides a dolly including a frame having a first end and a second end having at least one handle adjacent the first end of the frame, and at least one platform or support element extending from the frame proximate the second end. As is typical, at least two wheels adjacent the second end of the frame are configured to support the frame and platform for rolling movement. It is understood that the wheels themselves are not necessary to the invention (except for brake deployment) and are merely typical of existing dollies (the following discussion will refer to them as "wheels" in this convention). The new dolly has a lever member (consisting of a single or multiple lever elements) having a first end pivotally connected to the frame proximate the top or middle to bottom of the frame, and a second free end.

[0010] Where deployment of the lever members provides partial stair climbing, an engageable shoe assembly is pivotally connected to each side of the frame adjacent the second end, each shoe assembly configured to pivot its shoe portion to a support position extending below its respective wheel when desired. Thus, for non-standard small stair heights, it should be remembered that the use of the shoe assemblies is not necessary and engagement and use of the lever members alone, as described herein, may be sufficient to handle the load ascent, possibly without lever extension. Conversely, for standard stair heights, the operator may choose to disable the lever and rely solely on the shoe assemblies to reduce the step size.

[0011] The lever member is variably adjustable in length and includes a free end boot such that the free end of the lever member is flexible and can be variably positioned relative to a surface to provide a lever. The frame can be advantageously actuated as required to move the engaged shoe portion of each shoe assembly to a load-bearing position. Additional braking system features are described for the wheeled dolly as aiding in safely and controllably raising and lowering a load up a staircase. The braking system further includes a stabilizing mechanism that controls the brakes during descent after landing on each staircase to automatically brake the dolly, thereby preventing the dolly from sliding down the staircase. The brakes are then released to allow the dolly to continue its descent.

[0012] Thus, the trolley arrangement in one embodiment comprises a wheeled trolley: a) a frame having a first end and a second end; b) at least one handle adjacent said first end of said frame, typically extending from or accessible from a rear surface of said frame; c) at least one step or support element extending from a front side of the frame proximate the second end and configured to support a load; d) optionally, at least two wheels adjacent the second end of the frame and configured to support the frame and the platform for rotational movement (external or other means are included herein for movement to a lifting location); e) a mechanism provided at the rear of the frame configured to be repeatedly affected by the shifting of the center of gravity of the load on the dolly, the mechanism moving the dolly backward when the mechanism receives the pressure of the load caused by the shifting of the center of gravity backward toward the handle, thereby facilitating lifting of the dolly; and f) providing a stabilising support structure configured to support and stabilise said dolly and the load carried by said dolly in the raised position whilst the centre of gravity is returned.

[0013] In a further variation of this embodiment, the carriage device comprises: a. an integral lever member configured to be affected by a center of gravity shift, the integral lever member deployable to a lever position for engaging a higher step that allows the dolly and a load carried by the dolly to be lifted from a first wheel support surface to a lever position; b. a stabilizing support structure configured to support and stabilize the dolly and a load carried by the dolly at a lever position while the integral lever member is lengthened with a releasable extension element for lifting a second lever to a second wheel support surface; and c. A braking mechanism is provided that engages with the wheels of the dolly to prevent downward movement of the dolly without impeding upward movement of the dolly; The stabilizing support structure does not impede upward movement of the dolly, and the integral lever member, the releasable extension element and the stabilizing support structure are disengageable to repeat the lever, lifting and supporting operation.

[0014] As a further aspect of the present invention, the braking system and mechanism may be used independently and generally as a safety or control device for many other moving wheeled applications, such as wheelchairs, bicycles, shopping carts, strollers, prams, etc.

[0015] In a further embodiment, a series of lever elements are used in succession to effect lifting by the carriage over the entire distance of the riser, eliminating the use of said support stabilisation device.

[0016] This embodiment provides a heavy-duty lever dolly that achieves full lever lifting to riser height without the need for intermediate stabilizing members or support shoe elements as in the first embodiment. A further object is to provide a heavy-duty lever dolly having a structure in which a load is lifted from step to step with continuous lever actuation.

[0017] This embodiment comprises a method and apparatus for providing multiple lever lifts in close succession sufficient to traverse a stair rise height using multiple adjacent but hingedly separated lever members of different, adjustable lengths (if necessary). The lever members are hinged in succession to the top of the dolly frame with a common focal mount in a manner similar to the single lever member of the first embodiment. The height difference between the lever members is on the order of a typical rise height. The lever member closest to the dolly is the longest and is configured to engage the horizontal surface of a first step adjacent to a first dolly position and extends from a reference surface on which the dolly rests to just above the first rise height. The second lever member is a stair rise height shorter than the first lever member and extends approximately 2.25 rise heights from a reference surface on which the dolly rests, and the third lever member is an additional stair rise height shorter than the second lever member and extends approximately 3.5 rise heights from a reference surface.

[0018] With this arrangement, the first lever member is hinged back from the dolly towards the dolly user to engage the flat surface of the adjacent staircase as in the first embodiment and lever the load up a distance equivalent to a portion of the staircase rise height. A second, hinged, shorter lever member is then engaged to the flat surface of the next successive staircase and a second lever member is used to pivot the dolly and the load an additional distance of the rise height. A third, successive, shorter lever member is similarly deployed against the flat surface of the next successive staircase. The third short lever member is used to provide a lever drive to bring the load up to a height equal to the rise so that the dolly can be rolled or moved onto the flat surface of the first step. With such clearance, the respective lever members disengage from the step surface and collapse towards each other for the next deployment. Each lever member is controllably loosely attached by a spring-like attachment member to maintain the lever members at least slightly separated when separated via a hinge, and is also controllably loosely attached by a chain-like attachment member to prevent the lever members from separating excessively.

[0019] In this embodiment, the height of the dolly is greater than that of a standard dolly to accommodate the need for a user or operator to be more comfortable with additional lever arrangements. Two lever members could be used to achieve full rise height lift, but this may involve cumbersome modification of the dolly. Three lever members provide a structural arrangement for rapid rise height lift. However, it is understood that fewer additional lever members are also within the scope of the present invention.

[0020] In one aspect of the embodiment, the handle is attached to the dolly frame in a telescoping arrangement which can be moved and locked into normal and extended positions by focal attachment of a lever member, or, if desired, the telescoping arrangement includes intermeshing gear teeth such that when the desired height is reached, the gears intermesh to lock the handle in the desired height position.

[0021] To accommodate different conditions such as different rise heights, missing steps, and deployment at the top of a step (missing or limited engagement surface), the lever members are provided with a variable length structure as opposed to the single length boot of the single lever member in the dolly of the first embodiment. In a further variation of the embodiment, the change in length of the lever members may be achieved by the lever members being comprised of telescopic elements movable with engaged gears. Once the desired length is reached, the engaged gears are locked in place. In general, typical relative heights of the three lever members to effect positioning and segmented lifting are approximately 1 step rise height (typically 8") above the reference plane on which the dolly rests for the first lever member (closest to the dolly), less an additional approximately 1 and 1 / 4 step rise height (to accommodate angular positioning) for the second lever member (approximately 2 and 1 / 4 above reference plane), and less an additional approximately 1 and 1 / 4 step rise height for the third lever member (approximately 3 and 1 / 2 above reference plane).

[0022] The height or length of the lever member is changed so as not to interfere with other lever members.

[0023] In various embodiments, a dolly for easily lifting a load up stairs, each having a riser height, generally comprises: a) a frame having a first end and a second end; b) at least one handle adjacent the first end of the frame; c) at least one step or support element extending from a front side of the frame proximate the second end and configured to support the load; and d) Optionally, at least two wheels adjacent the second end of the frame and configured to support the frame and the platform for rotational movement.

[0024] According to an embodiment, the dolly further comprises a lever mechanism at the rear of the frame configured to be deployed under the influence of a shift in the centre of gravity of the load on the dolly, such that when the mechanism is subjected to the pressure of an applied weight rearwards towards the handle resulting from the continued shifting of the centre of gravity, the dolly is caused to move rearwards, facilitating lifting of the dolly above its full rise height and movement of the dolly with its supported load to the next staircase or supporting surface.

[0025] In a third embodiment, a dual lever element is constructed and arranged on the frame of the dolly to provide lift over the entire rise distance. In this third embodiment, the aim is to further simplify the construction of the dolly to provide a mechanical mechanism where a single continuous lever movement of the two lever elements provides sufficient lift for full height lift of a staircase with a heavy load.

[0026] This embodiment, like the previous embodiment, includes a dolly with an upper lever element (either adjustable length or a single standard length) hinged adjacent the top end of the dolly frame, and a handle. A second lever mechanism is hinged to the dolly frame at a height approximately one-third the standard dolly height of the dolly frame (the height position, however, depends on the span position of the second mechanism), or just over three standard steps (about 26 inches) above the base surface on which the dolly is supported.

[0027] The second lever mechanism comprises a freely rotatable lever element of sufficient length to rotate and extend to the rear end of a first step surface above the surface on which the dolly rests. The lever element is attached to a lifting member which lifts the lever element to a position where it can clear the edge of an adjacent stair rise for deployment onto the next step surface. Once deployed, the lever element is fixedly positioned in a unidirectional lever position. In one variation of this embodiment, the lever element is hingedly attached to the lifting element which is hingedly attached to the frame of the dolly. In such an embodiment, the lifting element and lever element provide a coaxial lever length with such fixed positioning.

[0028] In operation, the dolly with the load is approached to the stairs. The lever element is folded and raised above the height of the adjacent stair rise, then the lever element is fixedly placed in the lever position and extended across the surface of the step above the rise to the edge of the surface of the next rise or adjacent step. The dolly is then swiveled on the lever element until the upper lever element engages the step surface, often two steps above the engagement surface of the lower lever element (one or three steps are possible, but less common). The dolly continues to be levered or driven on the upper lever element until the wheels or base of the dolly have passed the first rise. The dolly is then trimmed with a forward movement, and the positioning and levering are repeated for each step. At the top step, after adjusting the length, the user simply moves backwards on the landing to allow the upper lever element to be positioned.

[0029] The above objects, features and advantages of the present invention will become more apparent from the drawings and discussion: BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate presently preferred embodiments of the invention and, together with the general description given above and the detailed description set forth below, serve to explain the features of the invention in the drawings: FIG. 1 is a front perspective view of a bogie according to an embodiment of the present invention.

[0030] FIG. 2 is a rear elevational view of the carriage of FIG. 1; Fig. 3 is a perspective view of the right side of the trolley of Fig. 1, and its mirror image of the left side; FIG. 4 is a front elevational view of the upper handle portion of the dolly of FIG. 1; FIG. 5 is a rear elevational view of the carriage of FIG. 1; FIG. 6 is a rear perspective view of the lower part of the carriage of FIG. 1; Fig. 7 is a right-hand side perspective view of the lower part of the carriage of Fig. 1, and its left-hand side is a mirror image thereof; FIG. 8 is a perspective view of an exemplary brake, stabilizer and shoe assembly of the dolly of FIG. 1; FIG. 9 is a front perspective view of an exemplary brake and shoe assembly as the cart moves up to the half rise of the stair step; 10-15 and 17 are side elevation views illustrating the operation of an exemplary dolly lever positioning and staircase progression in accordance with an embodiment of the present invention; FIG. 16 is a front perspective view of the brake and shoe assembly when the wheels of the carriage assembly are moving onto the stair tread; FIG. 18 is a side elevational view illustrating one method of operation of lever positioning and sequential movement of an exemplary cart from the staircase to the landing in accordance with an embodiment of the present invention; Figures 19A-E show the separated flexible boot and lever member (19A) in a free state (19B), an engaged state (19C), a stair guide (19D), and when engaged with a stair (19E) that is configured and used to extend the free end of the lever member; Figures 20A-C show the braking system with the stabilizer that controls the braking in separate exploded view (20A), engagement on the carriage / base (20B), and operation on stairs (20C).

[0031] FIG. 21 and FIGS. 21A-E show a second embodiment of a temporary position stabilization and support mechanism and a method for its deployment; 22A-F are sequential views showing the operation of a second embodiment of the cart of the present invention with multiple lever members, illustrating the structure of three lever members, when lifting a load up stairs without an intermediate lifting support stabilizer.

[0032] 23A-23E show the structure and sequential operation of a third embodiment of the dolly of the present invention, from the original arrangement with the dual lever member without the intermediate lifting support stabilizer (FIG. 23A), the lifting of the lever element to pass the step rise (FIG. 23B), the lever arrangement of the lever element (FIG. 23C), the initial lever lifting of the dolly (FIG. 23D) and the completed lever lifting of the dolly (FIG. 23E).

[0033] Detailed Description of the Invention In the drawings, like numerals refer to like elements throughout. Certain terms are used herein for convenience only and are not to be taken as limiting the present invention. Preferred embodiments of the present invention are described below. However, based on the present disclosure, it should be understood that the present invention is not limited by the preferred embodiments described herein.

[0034] [Embodiment with single lever and intermediate support mechanism] With reference to Figures 1-9, an exemplary stair climbing dolly 10 according to a first embodiment of the present invention will be described. With reference to Figures 1-4, the dolly 10 shown includes a typical generally lever-like main frame 12. The main frame 12 includes at least two uprights 12a on one side of the main frame 12 and a plurality of cross members 12b extending generally perpendicularly between the uprights 12a. At a first end proximate the frame 32b are a pair of handles 38 that allow the dolly 10 to be grasped during movement, particularly while ascending or descending stairs. An additional set of lower handles 18 are also provided for use as needed. Although not shown, the pair of handles may be replaced by a functionally equivalent single handle set, for example an arc-shaped handle set that extends across the width of the frame and can be grasped with both hands. At least two wheels 14 are shown rotatably engaged with the frame 12 proximate a second end of the frame 12. Preferably, wheels 14 extend outwardly from uprights 12a of frame 12 to enable dolly 10 to roll along a surface (not shown). Extending outwardly from the front of frame 12 proximate the second end is a lifting surface or platform 16. Preferably, at least a portion of platform 16 extends generally vertically in front of frame 12 to enable carrying and transporting of objects such as boxes (not shown).

[0035] 2, 3, 6 and 7, an optional pair of standard lift assemblies 20 are supported on the rear of the second end of the frame 12. Each standard lift assembly 20 includes a secondary frame member 22 extending from a respective upright 12a. A track 24 is supported by each secondary frame member 22, and a continuous belt 26 extends around the track 24. Bearings 27 or the like extend between the track 24 and the belt 26 such that the belt 26 is movable around the track 24. When the dolly 10 is tilted against a stair tread or the like, the standard lift assembly 20 assists the dolly 10 in moving against the belt 26 contacting the tread. In certain embodiments, the secondary frame member 24 and the continuous belt 26 may be integral with the standard lift assembly 20 or may be in place of the standard lift assembly 20. This portion of the dolly 10, other than the two sets of handles, is generally as described in the prior art device identified above. However, such devices still require significant effort by the person using the dolly in that the person must carry most of the weight of the load at some point during travel up and / or down stairs when the primary wheels are not on a horizontal surface. The lever assembly 30 and shoe assembly 50 described below assist in the movement of the dolly 10 up stairs or the like. Prior art dollies may be modified to add the lever assembly 30 and / or shoe assembly 50, or the dolly 10 may be manufactured as a uniform device, preferably with both the lever assembly 30 and shoe assembly 50 built directly into the frame 12 or the like.

[0036] 1-6, a lever assembly 30 according to an embodiment of the present invention will be described. In this embodiment, the lever assembly 30 includes a lever frame 32 extending from the main frame 12 having a pair of uprights 32a and at least one cross member 32b. A pair of drive handles 38 extend from the lever frame 32 and are configured to pivot the dolly 10 relative to a lever member 40 pivotally attached to the cross member 32b at hinges 37. Although this embodiment includes a lever frame 32 and drive handles 38, it will be understood that the lever member 40 may alternatively be hinged directly to one of the cross members 12b of the main frame 12 and the primary handle 18 may be utilized for pivoting. That is, the main frame 12 may define the entire frame, as opposed to the main frame 12 and the lever frame 32 defining the entire frame.

[0037] The lever member 40 preferably has a first tube member 40a and a second tube member 40b telescopically interconnected at a lockable joint 42. In this embodiment, a toothed bar 44 extends along the tube member 40a and is engaged by a handle 46a supported by the joint 42. The handle 46a is movable between an unlocked position and a locked position, where the unlocked position is a position in which the handle 46a does not engage the toothed bar 44 and the tube members 40a and 40b can move axially relative to one another to adjust the length of the lever member 40. The locked position is a position in which a portion of the handle 46a engages the teeth of the toothed bar 44, thereby locking the relative axial position of the tubes 40a and 40b and thereby fixing the length of the lever member 40. A lever handle or cross bar 36 extends from the lever member 40 and can be utilized to control the swing of the lever member 40 without releasing the handle. Preferably, the lever handle 36 is in close proximity to the drive handle 38 so that the user can easily move his or her fingers between the handles 36 and 38 while ascending or descending, as described below. While this embodiment includes a toothed bar 44, it will be appreciated that the telescopically interconnected tubular members 40a and 40b may be secured by any lockable telescopic mechanism that is easily adjustable during operation, such as a clamp or ratchet style lock or pin, and any other length adjustment mechanism may be used as well. Furthermore, if the required lever length is known, one full length lever with a boot is sufficient for most stair conditions. It should be noted that in one embodiment with respect to standard stair dimensions, the dolly frame is a standard height of about 60 inches with the lever length reaching between about 41 inches and about 60 inches.

[0038] The free end 41 of the lever member 40 extends and is pivotally connected to the boot 46 via a pivot pin 43. The pin 43 preferably extends through an axial slot 49a (see Figs. 6, 19A-E) through the free end 41 such that the boot 46 is pivotally and axially movable relative to the lever member 40. A second pin 45 extends across the boot 46 and is configured to engage a transverse notch 49 in the free end 41 of the lever member 40 to lock the lever member 40 and boot 46 in axial alignment and prevent pivoting therebetween, as will be described below. The free end of the boot 46 defines a contact surface 48, preferably of a non-slip material such as rubber.

[0039] 6-9, exemplary shoe assemblies 50 according to an embodiment of the present invention will be described. Each shoe assembly 50 includes a support block 52 configured to rotate relative to the main frame 12. In the embodiment shown, a common axle 55 extends through each wheel 14 and each support block 52. Thus, the weight of the dolly 10 is transferred from the main frame 12 through the axle 55 to either the wheels 14 or the support blocks 52 and thus to the shoe assemblies 50, as described below.

[0040] In stair climbing embodiments of the present invention, it may be desirable to stack the load being carried vertically to raise the load's center of gravity, thereby increasing the leverage provided by lever member 40. Thus, in certain stair climbing embodiments, it is preferred to have the center of gravity of the load being carried as high and as close to frame 12 as possible to maximize the benefits of the present invention.

[0041] A connecting bracket 54 is secured to each support block 52 and configured to rotate therewith. A hinge 56 extends between the connecting bracket 54 and a respective shoe 60. Each shoe 60 includes a support frame 62 and a contact surface 64. In the illustrated embodiment, the support frame 62 has a triangular configuration with a central support plate 63 (see FIG. 9). However, the support frame 62 may have other configurations suitable for supporting the weight of a loaded dolly 10. The support blocks 52, brackets 54 and shoes 60 are configured such that the wheels 14 are supported spaced apart from the surface when the shoe contact surface 64 engages the surface. As an example, the wheels 14 may be supported approximately 4 inches from the surface, which is approximately half the standard stair rise height. Thus, for non-standard small stair heights, it should be remembered that the use of a shoe assembly is not necessary and the lever members engaged and used as described herein above are sufficient to advance the load as it is raised. Conversely, for standard stair heights, the operator may choose to disable the levers and rely solely on the shoe assembly step reduction.

[0042] Each shoe 60 is preferably configured to be driven about the hinge 56 from a disengaged position (FIGS. 10 and 11), in which the shoe 60 does not interfere with normal operation of the wheels 14, to an engageable position in which the shoe 60 can rest on a surface (see, e.g., FIG. 16) or be driven to the position illustrated in FIG. 9. The shoes 60 are in one of four positions: a) locked closed, b) ready to deploy, c) deployed, and d) hinged out of the way, providing minimal profile and interference with stair and landing structures.

[0043] In the illustrated embodiment, a cord 65 extends from each shoe 60 to a connector 68 (see FIG. 1). The connector 68 can be connected to an upper connection point 67 on the main frame 12 or a lower connection point 69 on the main frame 12. When the cord 65 is connected to the upper connection point 67, the shoe 60 is maintained in a disengaged position, and when the cord connector 68 is moved to the lower connection point 69, the shoe 60 is placed in an engageable position. Although a cord is described herein, other mechanisms, such as levers, pins, etc., may be utilized to maintain the shoe 60 in a desired position. In various embodiments, the engagement of the shoe 60 is optional and can be engaged based on the height of the staircase, the weight of the load to be carried, and the maneuvering space. In some embodiments, the cord includes a spring 66 as part of its length to facilitate disengagement of the shoe as the load moves from one position to the landing. Referring to FIG. 18, placing the cord 65 at a higher position provides more tension for the spring 66 at increased tension. Thus, the shoe automatically folds when the dolly is lifted off a flat surface. The support distance of the shoe from the support surface is generally the same as that of the boot. While using the dolly on a flat surface, the shoe can be folded all the way up so as not to get in the way of use.

[0044] The illustrated dolly 10 also includes a brake member 70 and a stabilizer bar 80 associated with each wheel 14. Referring to FIG. 8, each brake member 70 has a U-shaped (which may be of different shapes depending on the shape of the wheels) configuration with a pair of side members 72 and a contact surface 74 extending therebetween. The side members 72 are drivingly connected to the subframe 22 (or any brackets behind the wheels) via pivot pins 73 such that the brake member 70 can swing between a disengaged position in which the contact surface 74 is spaced from the wheels 14 and an engaged position in which the contact surface 74 is in contact with a lower hemisphere of the wheels 14 (one of which is preferably a non-skid material such as rubber) so that forward rotation, such as down stairs, is prevented while rearward movement, such as up stairs, is permitted. In this manner, the brake member 70 prevents undesired forward movement, such as rolling down stairs.

[0045] A chain 75 (part of which may be a spring 76) extends from the brake member 70 proximate the contact surface 74 to a connector 78 (see FIG. 1) which may be connected to an upper connection point 77 on the main frame 12 or a lower connection point 79 on the main frame 12. When the chain 75 is connected to the upper connection point 77, the brake member 70 is maintained in a disengaged position, and when the chain connector 78 is moved to the lower connection point 79, the brake member 70 is placed in an engaged position. In this manner, the brake member 70 may be engaged when ascending stairs and disengaged when forward movement is desired, such as when descending stairs or traveling on a flat surface. Although a chain is described herein, other mechanisms may be utilized to maintain the brake member 70 in a desired position, such as levers, pins, etc.

[0046] 7, 8, 20A, B, and C, a stabilizer bar 80 is drivingly connected to the main frame 12 at drive point 82. The stabilizer bar 80 includes a notch 86 (used only when descending stairs) that is engageable with the brake member chain 75. If the back 80b of the stabilizer bar 80 (which projects from the back of the dolly) engages the edge of the upper step at 80a while the notch 86 is connected to the brake member chain 75, the descending dolly 10 will land in a braked position because the rear end 80b of the stabilizer bar 80 cannot descend with the dolly.

[0047] The stabilizer riser rotates at the drive point 82 and the front end of the stabilizer 86 moves downwards, automatically pulling the chain 75 down (the chain can be pulled this low because of the spring 76 in its center) with the stabilizer connected to the upper connection point. This action results in the same braking position as when the chain is connected to the lower connection point, for example, the full braking position. As the dolly lands on each of the lower steps (during its descent), the stabilizer is released from the edge of the upper step by pushing the dolly forward towards the standing position. The spring 76 then pulls up the chain 75, releasing the wheels from the brake. This allows a safer landing on the remaining steps.

[0048] Although the braking system above has been specifically described with respect to a dolly embodiment, a similar structure adapted to the wheels and configuration of a particular wheeled device can be incorporated into any wheeled device or conveyance to provide automatic braking operation when desired.

[0049] Having generally described the components of the exemplary dolly 10, its operation will now be described with reference to Figs. 9-16. With reference to Figs. 10 and 11, the dolly 10 is configured for normal, non-climbing operation in that each string 65 is connected to an upper connection point 67 such that the shoes 60 are in a disengaged configuration, and each chain 75 is connected to an upper connection point 77 such that the brake members 70 are in a disengaged position. The dolly 10 can be wheeled (or otherwise moved) relative to a surface 100 by tilting the frame 12 via the wheels 14 and via the handle 18. As shown in Fig. 11, the dolly 10 can be moved in the direction of arrow A such that the belt 26 is positioned near the base of a set of stairs 101 located adjacent to the first step 102a. Each step 102a, b, c... includes a riser 103 and a tread 104. With the dolly 10 so positioned, the lever assembly 30 and shoe assembly 50 may be utilized to assist in moving the dolly 10 up, or climbing, a set of stairs 101 .

[0050] 12, to allow the dolly 10 to climb, the shoe assembly 50 and brake member 70 are adjusted by moving the strings 65 and chains 75. That is, each string 65 is moved to the lower connection point 69 as shown by arrow B so that the shoes 60 are in an engageable position. Also, each chain 75 is moved to the lower connection point 79 as shown by arrow C so that the brake member 70 is in an engaged position. The dolly is now in an angular position relative to the operator (the lever member should be oriented in the same direction as the dolly). The ascending sequence is greatly aided by the selection of the lever position of the lever member by the skilled operator thereafter. Thus, as shown in FIG. 12, in one embodiment, the lever handle 36 is used to drive the lever member 40 about the hinge 37 so that the free end 41 is located adjacent the tread 104 of the second step 102b. The first step 102a is left clear so that the wheels 14 move to the tread 104 during the initial part of the lifting sequence. It is also possible that the free end 41 is located close to the tread surface of the third step 102c.

[0051] In this embodiment, the selection of the target location is in the front half of the step close to the edge. Once positioned closely together, the tubes 40a and 40b are adjusted relative to one another until the free ends 41 are located on the tread 104, as shown by arrow E. The handle 46a is re-engaged with the toothed bar 44 so that the length of the lever member 40 is fixed. It is noted that at this stage, the boot 46 is rotated about the pivot pin 43 so that the boot 46 is flush with the tread 104, preferably facing towards the dolly 10. Those skilled in the art will appreciate that the lever member 40, toothed bar 44 and boot 46 can be adjusted and positioned based on the height of the staircase, the depth of the staircase and the weight of the load being carried to obtain the desired lever and lift, which can vary from operator to operator and load to load in terms of preference. The length of the lever member 40 with the boot 46 can be dimensioned in some embodiments to compensate for staircase defects or for use with staircases of different height dimensions. The rigid extension provided by the pivotal movement and pressure lock of the boot 46 can be deployed or released without manually disengaging the handle.

[0052] 13, with the lever member 40 thus positioned, a swinging force is applied to the drive handle 38 as shown by arrow F. With the free end 41 of the lever member 40 engaged with the tread 104 and the belt 26 and wheels 14 abutting against the raised portion 103 of the first step 102a, the drive force moves the dolly 10 upward as shown by arrow G. As the dolly 10 moves upward, the shoes 60 are free to drive about their respective hinges 56 until the contact surfaces 64 are on the surface 100 and the dolly 10 is maintained elevated by the support frame 63 and support blocks 52 as shown in FIGS.

[0053] 14, with the above position selection in mind, the dolly 10 is driven via the drive handle 38 in the direction indicated by the arrow H. As the dolly 10 is pivoted, the shoe assembly 50 maintains contact and allows pivoting based on the pivot connection of the support block 52 to the frame 12.

[0054] When the dolly 10 is swung forward as indicated by arrow H, the lever member 40 is automatically lifted as indicated by arrow I and the boot 46 swings against the free end 41 until the contact surface 48 rests on the tread 104. The handle 36 can be used to control and direct the positioning of the lever and the boot. As more clearly depicted in Figs. 19A-E, the free end 41 of the lever member 40 engages with the pin 45 of the boot 46. The boot 46 remains completely stationary and rigid as if it were one piece with the lever as long as pressure is maintained through the boot on the tread (releasing such pressure can drive the boot 46 back to its original position). Thus, the swinging force is transmitted through the lever member 40 and the boot 46 to the contact surface 48. The contact surface 48 engages the tread 104 with an engagement pressure that is held in place against the retaining pin 45. The boot 46 preferably has a height approximately equal to the height of the shoe 60, so that the lever member 40 and the boot 46 together define a lever arm similar to the original lever arm without the boot 46 and shoe.

[0055] With further reference to FIG. 15, to complete the movement of the dolly 10 onto the tread 104 of the first step 102a, a pivoting force is again applied to the drive handle 38, as shown by the arrow J. Thus, the pivoting force causes the dolly 10 to move upward, as shown by the arrow K. As the dolly 10 moves upward, the wheels 14 clear the raised portion 103 of the first step 102a, and the wheels 14 are free to move onto the tread 104 of the second step 102b. Due to the driving nature of the support block 52, the shoe assembly 50 simply pivots as the dolly 10 moves onto the tread 104 of the first step 102a, as shown in FIG. 15 and FIG. 16. With reference to FIG. 17, once the dolly 10 is fully resting on the tread 104 of the first step 102a, the procedure can be repeated to move upward to another step.

[0056] Although it is preferred to position the free end 41 of the lever member 40 on the second step 102b, in certain embodiments the placement of the free end 41 can vary based on the desired lever, space constraints, and other operational considerations that would be understood by one of ordinary skill in the art. It is noted that under any positioning strategy, the operator's choice of lever positioning may vary from step to step, especially as the load moves from the step to the landing.

[0057] In this regard, the operator can lengthen the lever to make it easier to adjust the positioning strategy, as shown in Figure 18, where the shoe strap 65 includes a spring 66 in its center. This spring (or a similar member) is useful when lifting the dolly onto a landing where space is limited.

[0058] Since the landing has limited space, the dolly must be placed in a standing position which causes loss of space for opening the shoes between the bottom and the wide load, and the spring 66 automatically closes the shoes when lifting the shoes from the lower step of the landing. When the dolly is placed with the shoes open, as shown in Figure 18, the string 65 is attached to a higher connection point which stretches the spring 66 so that the shoes automatically close when the load pressure is released (by lifting the dolly). When the dolly is in a position to be lifted onto a small loan, the lever is extended much more than usual, replacing the height of the two and a half missing steps. In this case, the lever is not placed at an incline as is normal, but at a slight opposite angle. This position is necessary to solve the problem of lack of space and to bend the dolly into an inclined position. Some operators at this landing may find the availability of a second set of handlebars at a lower height useful in any case. This second set of handlebars also facilitates the conventional operation of the dolly in surface transfer of the load on the ground or other surface.

[0059] 21, instead of the previously described stabilizing shoe structure 50, the dolly includes hinged stabilizing triangular elements 150 located across the top and rear of the dolly and on and adjacent to the wheels as stabilizing elements to prevent the dolly from backing up during lever extension as described above in the shoe embodiment. The triangular elements 150 are spring loaded by springs 151 and are prevented from reversing by chains 152 (more clearly seen in FIG. 21A).

[0060] Figures 21A-E sequentially depict the lifting operation of the dolly 10 in which the triangular element 150 pivotally connected to the bracket 20 at 150b provides positional stability during extension of the lever member 40. As shown in Figure 21A, the triangular element 150 is supported by the stair edge 102a under spring compression and does not impede the upward movement of the dolly to level the step 104. When the lower edge 150a passes the stair edge 102a due to the lever exerted via the lever member 40, the compression spring 151 pushes the triangular element 150 and rotates it to the step 104 engaging position shown in Figure 21B.

[0061] This retards or prevents downward or rearward movement of the dolly 10 and load during release of the lever member 40 (with movement H) shown in Figure 21C, by lengthening at section 46. As the dolly is raised up to the step 104, as shown in Figure 21D, the step edge 102b pushes the triangular portion 150 back into a retracted position which does not impede further subsequent upward movement.

[0062] As with the previous embodiment, the lengthened lever member is used to lever the cart further up to the higher or second step, once pressure is released on lever member 40 and extension 46 is returned to its original position as shown in FIG. 21E.

[0063] The lever is used to raise the cart, the position is stabilized, and the lever member is extended by raising and lowering the second lever, and the operation continues until the cart passes the step. The braking procedure and the braking element are configured to prevent backward slipping and control the descent of the stairs with a load, as in the previous embodiment, and to move backward when the cart is in the descending operation. (Embodiments with multiple lever elements) 22A-F show a second embodiment of an exemplary dolly 110 with a handle with an extendable extension 138a elevated above a standard height handle 138b for ease of operation, and a lever lift mechanism with a three lever mechanism 140 hinged at 137 to the top of the dolly frame 110a. As shown, the three lever mechanisms 140 have a common hinged focal point 137, and the length of each lever member (140a, 140b, 140c of varying heights, successively shortened by the approximate step riser height) is configured to be adjustable by handles 146a, 146b, 146c, respectively, to engage the subsequent steps 114, 116, 117, respectively, as shown in the respective drawing sequence.

[0064] 22A-F, each lever action by the lever members lifts the cart off the surface 113 and successively raises the supported load up the height 114a of the stair step 114 relative to the step spacing. Once the cart 110 and load have cleared the step, the hinged lever members fold together and move forward to repeat the procedure for each subsequent step.

[0065] The sequence shown in Figures 22A-F is repeated for each subsequent step. Figure 22A shows the wheel 14 brought into position adjacent the step rise 114a of the step 114. The end 141a of the lever member 140a is brought into position for direct engagement with the flat surface of the step 114 by pulling the handle 138a in the direction of the arrow and rearward movement of the dolly 110 by operating the handle 136. Figure 22B shows that further rearward pulling of the handle 138a causes the shorter lever member 140b to engage the flat surface of the subsequent step 116 at the lever member tip 141b (by approximately a step rise height). Continued pulling of the handle 138a as shown causes lever action of the dolly 110 on the lever members 141a and 141b with upward movement of the wheel 14 for a partial rise distance of the adjacent rise 114a.

[0066] As shown in Figure 22C, the shortest lever member 140c at lever member tip 141c engages the flat surface of step 117. As handle 138a continues to be pulled, lever member 140a is lifted off the flat surface of step 114, and lever members 140b and 140c act to provide further leverage to lift wheel 14 against riser 114a. In Figures 22D and 22E, continued levering with lever member 140c further lifts wheel 14 past the height of riser 114a. Wheel 14 can rotate and rest on the flat surface of step 114.

[0067] The folded lever members 140a-c (with release of support pressure) are then advanced as shown by the arrows in FIG. 22F. The lever members 140a are then engaged with the next subsequent flat surface of the step 116 to lift the wheel 14 above the rise height 116a in successive step repetitions shown in FIG. 22A-E. At the top of the staircase, the spacing of the different length lever members 140-c on the landing serves to perform the final lever lift. In this embodiment, multiple lever members substitute for intermediate position stabilization with full rise height lift by successive lever steps.

[0068] The lever member may be pre-lengthened by height adjustment prior to use in stair measurement, or may be height adjusted by a separate handle and locking element during the actual lifting procedure.

[0069] [Embodiment of hybrid levering structure] In a third embodiment, as seen in Figures 23A-E, the mechanical dolly 210 includes a first lever element or rod 240 hinged to the dolly frame 210a at its upper end 237 adjacent to a handle 238. The lever element 240 optionally includes a length adjustment handle 246 at its tip 241 for optional length adjustment.

[0070] As shown, the second lever mechanism includes a first lifting member 340 a hingedly attached by hinge 337 to the dolly at approximately one-third the height of the standard dolly frame 210 .

[0071] Lifting member 340 is hinged to lever element 340b at approximately the middle of its length by hinge element 337a and support element 350. Chain 339 and spring member 342 between lifting member 340a, lever element 340b, and carriage-frame 210a maintain loosely controlled positioning of lever mechanism 240 and 340 elements relative to carriage 210 in the initial rest position of FIG. 23A. Carriage wheel 250 rests on initial step 214 and initial flat surface 213 adjacent rise 214a. Free end 341 rests near surface 213 adjacent rise angle 214a'.

[0072] In the initial operation shown in Fig. 23B, the movement of the lever element 340b is blocked from the lever position by the riser 214a so that the lever element 340b is folded to a nearly vertical position relative to the lifting member 340a via the hinge 337a. The lever element 340b is lifted by the lifting member 340a with the control string 343 (and handle 343a) to pass the adjacent riser edge 214b. The chain 339 limits the lift separation and the spring 342 serves to return the lever element 340b and the lifting member 340a to the original longitudinal arrangement shown in Fig. 23C after the lever 340 has passed the edge 214b.

[0073] The lifting member 340a, lever element 340b and the end of lever element 341 are then brought into proximity with the junction 215 between the step surface 214 and the next riser 216a. As shown in Fig. 23D, the cart 210 is driven and levered about the lever element 340b, partially lifting the load, to provide a second successive lever, until the upper lever element 240 engages the higher step plane 217 and the cart passes the riser 214a and is moved up to the plane of the step 214 as shown in Fig. 23E. As with the previous embodiment, the repetition is accomplished by the forward movement of the cart and the folding of the elements of each successive step to the position shown in Fig. 23A.

[0074] Those skilled in the art will appreciate that changes or modifications may be made to the above-described embodiments without departing from the broad inventive concept of the present invention. It should therefore be understood that the present invention is not limited to the specific embodiments described herein, but is intended to include all changes and modifications within the scope and spirit of the present invention as defined in the appended claims, and elements that are equivalently operable thereto. Furthermore, while the above description and drawings include prior art elements related to the transportation system, it should be understood that these are illustrated for the purpose of improving existing dollies. However, the structures and elements of the present invention are independently operable with or without the prior art elements. [Brief description of the drawings]

[0075] [Figure 1] FIG. 2 is a front perspective view of the bogie according to the embodiment of the present invention. [Diagram 2] FIG. 2 is a rear elevational view of the dolly of FIG. 1. [Diagram 3] 2 is a right side perspective view of the bogie of FIG. 1, and the left side is a mirror image thereof. [Figure 4] FIG. 2 is a front elevational view of an upper handle portion of the dolly of FIG. 1. [Diagram 5] FIG. 2 is a rear elevational view of the dolly of FIG. 1. [Figure 6] FIG. 2 is a rear perspective view of the lower part of the dolly of FIG. 1. [Figure 7] FIG. 2 is a right side perspective view of the lower part of the bogie of FIG. 1, and the left side is a mirror image thereof. [Figure 8] FIG. 2 is a perspective view of an exemplary brake, stabilizer and shoe assembly of the dolly of FIG. [Figure 9] FIG. 1 is a front perspective view of an exemplary brake and shoe assembly as the cart moves up to the half rise of a stair step. [Figure 10] 11A-11C are side elevational views illustrating an exemplary method of operation for lever positioning of the dolly and sequential movement of stairs in accordance with an embodiment of the present invention. [Figure 11] 11A-11C are side elevational views illustrating an exemplary method of operation for lever positioning of the dolly and sequential movement of stairs in accordance with an embodiment of the present invention. [Figure 12] 11A-11C are side elevational views illustrating an exemplary method of operation for lever positioning of the dolly and sequential movement of stairs in accordance with an embodiment of the present invention. [Figure 13] 11A-11C are side elevational views illustrating an exemplary method of operation for lever positioning of the dolly and sequential movement of stairs in accordance with an embodiment of the present invention. [Figure 14] 11A-11C are side elevational views illustrating an exemplary method of operation for lever positioning of the dolly and sequential movement of stairs in accordance with an embodiment of the present invention. [Figure 15] 11A-11C are side elevational views illustrating an exemplary method of operation for lever positioning of the dolly and sequential movement of stairs in accordance with an embodiment of the present invention. [Figure 16] FIG. 1 is a front perspective view of the brake and shoe assembly as the wheels of the cart assembly are moving onto the stair tread. [Figure 17] 11A-11C are side elevational views illustrating an exemplary method of operation for lever positioning of the dolly and sequential movement of stairs in accordance with an embodiment of the present invention. [Figure 18] 11A-11C are side elevation views illustrating one method of operation of lever positioning and sequential movement of an exemplary cart from a staircase to a landing in accordance with an embodiment of the present invention. [Figure 19] A separated flexible boot and lever member (19A) is shown in a free state (19B), an engaged state (19C), a stair guide (19D), and when engaged with a stair (19E) that is configured and used to extend the free end of the lever member. [Figure 20] The braking system with the stabilizing device that controls the braking is shown separately in exploded view (20A), engagement on the carriage / base (20B), and operation on the stairs (20C). [Figure 21] 1 shows a second embodiment of a temporary position stabilization and support mechanism and a method for its deployment. [Figure 22] 1 is a sequence of photographs illustrating the operation of a second embodiment of the trolley of the present invention with multiple lever members when lifting a load up stairs without an intermediate lifting support stabilizer, showing the structure of three lever members. [Diagram 23] 23A shows the construction and sequence of operation of a third embodiment of the trolley of the present invention, from the original arrangement with the double lever member without the intermediate lifting support stabilizer (FIG. 23A), the lifting of the lever element to pass the step rise (FIG. 23B), the lever arrangement of the lever element (FIG. 23C), the initial lever lifting of the trolley (FIG. 23D) and the completed lever lifting of the trolley (FIG. 23E).

Claims

1. a) a frame having a first end and a second end; b) at least one handle adjacent the first end of the frame; c) at least one load supporting element extending from a front surface of the frame proximate the second end and configured to support a load; d) optionally, at least two wheels adjacent the second end of the frame and configured to support the frame and the load bearing element for rotational movement; and e) a mechanism behind the frame configured to be repeatedly affected by the shifting of the center of gravity of the load on the carriage; The mechanism facilitates lifting of the dolly by moving the dolly backwards when the pressure of the applied weight resulting from the shift in the center of gravity is felt backwards toward the handle.

2. the dolly further comprising a stabilizing support structure configured to support and stabilize the dolly and a load carried by the dolly in the raised position during return of the center of gravity; the stabilizing support structure includes one of a shoe assembly drivingly connected to each side of the frame proximate the second end, each shoe assembly configured to be driven into a support position with a shoe portion thereof extending below a respective wheel and extending away from the frame; an elongated triangular configuration disposed parallel to the frame and facing the load; The dolly of claim 1 , wherein sides of the triangular formation act as support surfaces when the triangular formation is rotated.

3. the mechanism affected by centre of gravity movement optionally comprises a length adjustable lever member having a first end drivingly connected to the frame adjacent the first end of the frame, and a second free end; The dolly of claim 1 , wherein the free end of the lever member is configured to be placed against a surface and the frame is configured to actuate adjacent to the lever member.

4. the free end of the lever member includes a movable boot member that maintains a position aligned with the lever member when in direct compressive engagement with a surface of the step and is bendable and out of alignment with the lever member when disengaged from the surface and engaged with a riser of the step; 4. The dolly of claim 3, wherein the movable boot member is deployable into alignment with the lever member and movable out of alignment with the lever member without releasing manual control of the handle by a user thereof.

5. 1) an integral lever member deployable to a lever position for engaging a higher step that allows the dolly and a load carried by the dolly to be lifted from a first wheel support surface to a lever position; 2) while the integral lever member is lengthened with a releasable extension element for lifting a second lever onto a second wheel support surface; a stabilizing support structure configured to support and stabilize the dolly and a load carried by the dolly in a raised position; 3) A braking mechanism that engages with the wheels of the carriage to prevent downward movement of the carriage without impeding upward movement of the carriage; 2. The dolly of claim 1, wherein the stabilizing support structure does not impede upward movement of the dolly, and the integral lever member, the releasable extension element and the stabilizing support structure are disengageable to repeat the lever, lifting and supporting operation.

6. 2. The dolly of claim 1, characterized in that the dolly is provided with a position-retaining structure that prevents the dolly from returning to its original position when the mechanism allows lifting below the stable position, whereby resetting the return of the mechanism is achieved without losing the lifted position achieved.

7. The dolly of claim 1, wherein the mechanism affected by center of gravity shifting has an automatic actuation structure that can be reset upon return for further lifting and subsequent center of gravity shifting without the operator of the dolly releasing the handle of the dolly.

8. 10. The dolly of claim 1, wherein the dolly has at least two wheels, at least one of the wheels being provided with a controlled wheel rotation stopping and braking mechanism configured to prevent rotation of the wheel in an undesired direction while allowing rotation in a desired direction.

9. 9. The truck of claim 8, wherein the stopping and braking structure is configured to automatically engage the wheels with effective braking and to retract into engagement as the wheels rotate upon initiation of rotation of the wheels in an undesired direction.

10. 9. The dolly of claim 8, wherein the stopping and braking structure is configured to be automatically activated upon the dolly landing on a step during its downward travel.

11. the stop braking arrangement includes a mechanism configured to control a stop braking operation to provide desired braking without manual control; 9. A dolly as claimed in claim 8, further comprising a stabilising mechanism including a control mechanism that allows an operator of the dolly to activate or deactivate a stopping and braking arrangement when desired, without the operator having to release control of a handle of the dolly.

12. two sets of handles adjacent the first end of the frame and spaced apart from one another along a length of the frame; The dolly of claim 1 , wherein the two sets of handles are positioned and configured to facilitate handling and control of the dolly during movement of the dolly up and down stairs while carrying a load.

13. 3. The truck of claim 2 having at least two wheels, the shoe assembly being supported on an extension of the axle connecting the wheels when the axle extends beyond the wheel having an extension.

14. 3. The dolly of claim 2, wherein each shoe is configured to fold against the frame when the dolly reaches the top of a staircase and a short landing, thereby limiting movement due to the expanded width of the dolly having a carried load wider than the width of the dolly.

15. 4. The dolly of claim 3, wherein the handle, which has an elongated lever member hinged at a focal point, is adjustable relative to the longitudinal height of the frame along a track within the frame.

16. A spring in the chain helps control the deployment of the stopping and braking structure; the stabilizing mechanism is deployed to lock the stopping brake element when the stabilizing mechanism engages a step edge or a step obstruction; The truck of claim 11 , wherein the spring releases the stop brake when the stabilizing mechanism moves away from the edge of the step or obstacle.

17. 1. A stopping and braking arrangement for a wheeled device, comprising: the stopping and braking mechanism comprises a controlled wheel rotation configured to permit rotation of the wheels in a desired direction while preventing rotation of the wheels in an undesired direction; the stopping braking structure is configured to automatically engage the wheel with effective braking and to be drawn into engagement with rotation of the wheel; wherein, with or without manual control, upon initiation of wheel rolling in an undesired direction, said stopping braking is automatically activated by a mechanism configured to control stopping braking operation of the structure to brake as desired; A stopping and braking structure for a wheeled device, comprising a stabilizing mechanism having a control mechanism that allows the stopping and braking structure to be activated or deactivated, when desired, on a wheeled device having a control element, without the operator of the wheeled device having to release control of the control element.

18. the stabilizing mechanism is disposed on the braking mechanism and comprises a lever element having a protrusion at one end, the protrusion being inserted into a spring that controls a chain; The lever element has a free second end, and the second end of the lever is configured to be lifted as a result of engaging with an obstacle of an edge or a step of a staircase, 18. The stopping and braking structure of claim 17, wherein when the lever second end is lifted, the projection urges the chain and brake into a braking position, and release of the lever end from the lifted condition results in release of the braking mechanism from the braking position.

19. the dolly further comprising a lever mechanism at the rear of the frame configured to be deployed as affected by a shift in the center of gravity of a load on the dolly; When the mechanism is subjected to the pressure of the applied weight resulting from the continued movement of the center of gravity rearward toward the handle, the dolly moves rearward, thereby 10. The dolly of claim 1, further comprising a step for lifting the dolly above a first riser height to facilitate moving the dolly with a supported load to the next staircase or supporting surface.

20. the lever mechanism comprises at least two elongated lever members hinged at their rear ends to the frame; 20. The dolly of claim 19, wherein the lever members are successively spaced from the frame and the heights of the lever members are successively shorter such that the elongated lever members can engage successive upper surfaces of stairs to effect simultaneous or successive lever lifting of the dolly having a load supported above the first riser height.

21. 20. The dolly of claim 19, wherein the lever mechanism comprises three elongated lever members hinged to the rear of the frame at focal locations adjacent at least one handle, each of the elongated lever members optionally including height adjustment structure to allow adjustment of the height at which the respective lever members engage successive upper surfaces of the staircase to effect simultaneous or sequential lever lifting.

22. 1. A dolly for easily lifting a load up a staircase step, each step having a riser height, comprising: The cart is a) a frame having a first end and a second end; b) at least one handle adjacent the first end of the frame; c) at least one load supporting element extending from a front surface of the frame proximate the front second end and configured to support a load; and d) optionally, at least two wheels adjacent the second end of the frame and configured to support the frame and the load bearing element for rotational movement; the dolly further comprising a lever mechanism isolated to the rear of the frame configured to be deployed as influenced by a shift in the center of gravity of a load on the dolly; When the mechanism is subjected to the pressure of the applied weight resulting from the continued movement of the center of gravity rearward toward the handle, the dolly moves rearward, thereby lifting the dolly above a first rise height of the step to facilitate moving the dolly with a supported load to the next step or supporting surface; The lever mechanism includes: i) an upper lever element adjacent to the at least one handle and hingedly attached to the frame adjacent its upper end; ii) a lower lever element adjacent its lower second end; and iii) a lifting element hinged to the lower second end of the frame and the lower lever element hinged to the lower second end; The lifting element is configured to lift the lower lever element sufficiently to clear an adjacent riser at the first riser height to allow the lever element to assume a lever configuration.

23. the lever element is disposed at a lower portion of the frame height from the second end; 23. The dolly of claim 22, comprising a mechanism that allows the lever element to be raised from step to step towards the contact point between the step face and the next riser while allowing the lever element to avoid blockage by a riser adjacent to the lever element.

24. A mechanical method for enhancing the capability of said dolly to move large capacity heavy loads up stairs and down stairs in a controllable manner, comprising: the dolly comprises a support frame having a first end and a second end, the first end being provided with a control handle and the second end being provided with a load-bearing element for supporting an element; The method includes the steps of: a) a lever member having a first end pivotally connected to the first end of the frame; providing a first end of the lever member with a second end of the lever member free, the free end of the lever member configured to be placed against a surface, the frame being pivoted adjacent the lever member; b) providing a dolly having an engageable and disengageable intermediate weight support or positional stabilization configured to be deployable after an initial lever lift and disengageable to extend an integrally hinged lever member to provide successive additional lever lifts without downward movement of the dolly; and c) providing the dolly with an engageable and disengageable braking structure configured to retard and control downward movement of the dolly during upward movement of the dolly.

25. The method of claim 24 further comprises the steps of: i. placing the dolly on a surface or plane adjacent to a first staircase and proximate to a rise of the first staircase; ii. extending an integrally hinged elongated lever member away from the dolly with a free end thereof supportingly engaging a second, higher step and using the lever member as a lever to raise the load against the rise of the first step; iii. deploying a load support structure to hold the load in place while the lever member is extended to provide additional lever lifting capacity; iv. using the extended lever member to lever the dolly out of its load-bearing holding location so that the wheels of the dolly can move further upwardly and onto the step of the second staircase; v. returning the lever member to its original length, releasing the load pressure; and vi. Repeating steps ii-v until the cart has passed the top floor and exited onto the landing, and the braking structure prevents unwanted backward movement during upward staircase travel.

Images