BACKGROUND OF THE INVENTION
1) Field of the Invention
The invention herein relates to mechanical rotation safety protection mechanisms, specifically an end surface gear-type overload protection device for manually operated hoists.
2) Description of the Prior Art
Conventional manually operated hoist structures are categorized into two types: hand crank type or hand chain type, wherein the “hand crank type” hoist, as shown in FIG. 13, is comprised of a load pulley wheel 2 ensconced along with a bearing device between a pair of side plates 1 as well as an operating drive component 3 disposed at the outer lateral extent of the side plates 1 that drives a transmission shaft 4 accompanied by a gear reduction mechanism 5 at its axial lateral extent, said drive component 3 consisting of a hand crank arm 3a having a single-direction drive ratchet wheel 3b, a pawl 3c, and a pawl spring 3d such that the rapid operation of the hand crank arm 3a turns the drive shaft 4 which pulls over said load pulley wheel 2 a chain 6 connected to a hoisting hook 6a coupled to a heavy object; the “hand pull type” hoist, as shown in FIG. 14, generally consists of, in common with the hand crank type structure, side plates 1, a load pulley wheel 2, a transmission shaft 4, a gear reduction mechanism 5, a chain 6 connected to a hoisting hook 6a, and other necessary drive components, the difference is that the power input section drive component 7 is instead a hand pull chain 7a and at its lateral axial aspect has a direction alternating ratchet wheel 8 and a pawl 8a which replaces the drive component 3 of said hand crank type structure, the hand pull type variant utilizing the hand pull wheel 7 over which is diametrically disposed a hand pull chain 7b to draw and thereby operate, at the other end of the transmission shaft 4, a load pulley wheel 2 and its chain 6 connected to a hoisting hook 6a coupled to a heavy object; since the hand crank type and the hand pull type structures are uncomplicated, portable, and convenient, they are widely used for loading cargo, unloading cargo, and strapping cargo. As such, in keeping with their operating characteristics, they are often utilized in an overloaded state and there is no limiting overload setting which, especially when lifting and strapping loads, tends to concentrate hoisting load stress at certain points, the hoisting hook 6a easily subjecting the chain 6, brake, and other components of the hoist to excessive wear, while also easily damaging goods and causing industrial accidents wherein operating personnel suffer injury.
SUMMARY OF THE INVENTION
The primary objective of the invention herein is to provide an end surface gear-type overload protection device for manually operated hoists, providing a hand crank type hoist or a hand pull type hoist that, in view of overload incurred wear or accidents attributed to such hoists in the past, integrates a safety device that senses a preset overload weight and, furthermore, automatically halts operation to thereby prevent hoisting rig damage and operating personnel industrial injury and accidents.
The unique features of the structure herein includes the utilization of a disc-shaped spring to control tension such that during leftward gear rotation and enmeshment normal operation continues, but during rightward rotation when instructions cannot be executed by the clutch-type gear installed to prevent overload and the invention is in the “overload prevention” operating mode, if the set load of the disc-shaped spring is exceeded, the clutch-type gear after sensing such allows the operating shaft to spin in neutral continuously. Additionally, said structure can be simply adjusted to a “non-overload prevention” operating mode to thereby permit operation under overload conditions.
As such, the end surface gear-type overload protection device for manually operated hoists of the invention herein is a structure capable of utilization in either a hand crank type hoist or a hand pull type hoist to provide such manually operated hoists a practical means of overload control.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded drawing of the first most preferred embodiment of the invention herein.
FIG. 2 is a cross-sectional drawing of FIG. 1, showing a partial aspect in magnified view.
FIG. 3 is an orthographic drawing of the drive component, umbrella type gear ring of the invention herein.
FIG. 4 is an orthographic drawing of the drive component, umbrella type gear ring of the invention herein.
FIG. 5 is an orthographic drawing of the drive component sleeve, umbrella type teeth section of the invention herein.
FIG. 6 is an orthographic drawing of the drive sleeve, umbrella type teeth section of the invention herein.
FIG. 7 is an isometric drawing of the locating ring and the adjustment nut of the invention herein.
FIG. 8 is an isometric drawing of the assembled locating ring and adjustment nut of the invention herein.
FIG. 9 is an orthographic drawing of the drive component and drive sleeve when engaged in forward rotation.
FIG. 10 is an orthographic drawing of the drive component and drive sleeve when engaged in rearward rotation.
FIG. 11 is an exploded drawing of the second most preferred embodiment of the invention herein.
FIG. 12 is a cross-sectional drawing of the second most preferred embodiment of the invention herein, showing a partial aspect in magnified view.
FIG. 13 is an exploded drawing of a conventional manual crank type hoist structure.
FIG. 14 is an exploded drawing of a conventional manual pull type hoist structure.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
To elaborate the “manual crank type” hoist structure of the present invention, as indicated in FIG. 1 and FIG. 2, the invention herein is comprised of two side plates 1, a load pulley wheel 2, a drive component 3, a transmission shaft 4, and a gear reduction mechanism 5, with a hand crank arm 3a that is turned rapidly to impel the transmission shaft 4, thereby causing the load pulley wheel 2, on which is mounted a chain 6, to draw a connected hoisting hook 6a coupled to a heavy object; since this aspect of the arrangement is identical with that utilized conventionally, it shall not be further described; the original design feature of the invention herein is that the drive component 3 ratchet wheel 3b, at its lateral area of rotation, includes an umbrella type gear ring 10, an elastic component 20, a drive sleeve 30, an adjustment nut 40, an equalizing washer 50, and a locating ring 60 in a insertional spatial arrangement, the unique features of which include:
Referring to FIG. 1 and FIG. 2, the umbrella type gear ring 10 and the ratchet wheel 3b end surface constituted into a single structural entity, the end surface consisting of slanted facets 11 postured at a predetermined angle and, as indicated in FIG. 3 and FIG. 4, the optimal angle α of each slanted facet 11 is 20 degrees, while situated perpendicularly at the terminus of each slanted facet 11 is a land section 12, and reticulated axially at the rear end of the drive component 3 ratchet wheel 3b is a recess 13.
Referring to FIG. 1 and FIG. 2, the elastic component 20 is seated in the recess 13 of the ratchet wheel 3b and is optimally a disc-shaped spring.
Referring to FIG. 1 and FIG. 2, the drive sleeve 30 is placed axially onto the transmission shaft 4, one end consists of a relatively large diameter holding flange 31 with the other end consisting of relatively narrow diameter hollow neck 32 and, as indicated in FIG. 5 and FIG. 6, the holding flange 31 has an umbrella type teeth section 311 consisting of inclined angle troughs and peaks that enmesh the umbrella type gear ring 10, the slanted facets 311A of which are each postured at a predetermined angle β, the optimum predetermined angle β of each slanted facet being 20 degrees, and situated perpendicularly at the terminus of each slanted facet 311A is a land section 311B; the hollow neck 32 is inserted axially through the umbrella type gear ring 10 and the ratchet wheel 3b and, furthermore, external threads 321 are died onto its extremity.
Referring to FIG. 2 and FIG. 7, the adjustment nut 40 is a rectilinear body and, furthermore, internal threads 41 are tapped through its center for fastening onto the external threads 321 at the extremity of the drive sleeve 30; a bottoming section 42 is machined flat along the front extremity and a quantity of notches 43 are disposed along the outer circumference; and two anchoring holes 44 are drilled diametrically in the end surface to position a shaft collar bearing 45 (see FIG. 1) in the bearing hole 3e of the hand crank arm 3a.
Referring to FIG. 1 and FIG. 2, the equalizing washer 50 is an annular rigid body that is disposed pivotally at the inner sides of the elastic component 20 and the adjustment nut 40 such that when the adjustment screw 40 is tightened, it provides equalized pressure axially against the elastic component 20.
Referring to FIG. 1 and FIG. 2, the locating ring 60 is an annular washer that is seated pivotally between the sides of adjustment screw 40 and the equalizing washer 50 and, as indicated in FIG. 7 and FIG. 8, has a bottoming flat surface 61 that corresponds to the bottoming section 42 along the front end of the adjustment screw 40 and, furthermore, six tabs 62 protruding towards the notches 43 to provide for the radial fixing by insertion of the adjustment screw 40 position.
Based on said assembly, the operation and utilization of the end section gear type overload protection device for manually operated hoists of the invention herein is as follows: Referring to FIG. 2, the adjustment screw 40 is fastened into the external threads 321 at the extremity of the drive sleeve 30 to axially clamp together the drive component 3 ratchet wheel 3b, the elastic component 20, the drive sleeve 30, the equalizing washer 50, and the locating ring 60, utilizing the adjustment screw 40 to produce axial pressure against the drive component 3 and, via the equalizing washer 50, apply balanced pressure against the elastic component 20 such that changes in its shape result in axial thrust which provides the required load torsion.
At the same time, the skewered and clamped drive component 3 ratchet wheel 3b at the end surface of the umbrella type gear ring 10 enmeshes the drive sleeve 30 umbrella type teeth section 311, as shown in FIG. 9 and FIG. 10, increasing the elastic component 20 rebound force, and thereby increasing the friction laterally exerted between the umbrella type gear ring 10 and the umbrella type teeth section 311, such that the drive component 3 ratchet wheel 3b requires the transfer of greater torsion before slippage occurs and conversely the transfer of less torsion to readily allow slippage; when a load exceeds the set torsion of the load pulley wheel 2 at the emergent tip of the transmission shaft 4, the hand crank arm 3a turning the ratchet wheel 3b slips to protect against inputted transmission overload.
As a result, when no overload occurs during the transmission process, the ratchet wheel 3b, the drive sleeve 30, the equalizing washer 50, and the locating ring 60 remain clamped together and, as such, given the alternating directional operation of the hand crank arm 3a ratchet wheel 3b with a pawl 3c, as indicated in FIG. 9, the two land sections 311B and 12 engage perpendicularly to achieve forward rotation or, as indicated in FIG. 10, the umbrella type gear ring 10 and the umbrella type teeth section 311 slanted facets 311A and 11 engage to achieve reverse rotation operation, and with the rapid up and down movement of the hand crank arm 3a, the transmission shaft 4 pulls the chain 6 mounted over the load pulley wheel 2 and thereby raises the hoisting hook 6a coupled to a heavy object.
When an overload occurs during the transmission process, the umbrella type gear ring 10 and the umbrella type teeth section 311 slanted facets 311A and 11 that were originally pushed and squeezed against each other are then impelled laterally to disengage the land sections 311B and 12, following which they fall into another engagement with the slanted facets 311A and 11 and, as a result, umbrella type gear ring 10 and the umbrella type teeth section 311 slip apart and spin in neutral, manifesting a metallic frictional sound that informs the operator of the overload, thereby ensuring work safety.
Additionally, the hand crank arm 3a and the transmission shaft 4 of the invention herein, at their lateral area of rotation, includes an umbrella type gear ring 10, an elastic component 20, a drive sleeve 30, an adjustment nut 40, an equalizing washer 50, and a locating ring 60 in a insertional spatial arrangement, and although utilized to provide for “overload prevention” operations mode with a procedure for setting hoist load limits, the present invention is easily adjusted into a “non-overload prevention” operations mode, the procedure only requiring the removal of the locating ring 60 tabs 62 that were originally inserted into said notches 43, which thereby releases the fixed state of the adjustment nut 40 to accommodate specific working requirements and, as such, tasks can be performed under overload conditions if desired because the adjustment procedure is very simple.
Referring to FIG. 11 and FIG. 12, to elaborate the invention herein utilizing a “manual pull type” hoist, the present invention is comprised of two side plates 1, a load pulley wheel 2, a drive component 7, a transmission shaft 4, and a gear reduction mechanism 5, via the drive component 7 hand chain wheel 7a and a hand chain 7b that rotate and are driven on the transmission shaft 4, wherein a chain 6 mounted over the load pulley wheel 2 draws a connected hoisting hook 6a coupled to a heavy object, and since these aspects of the arrangement are identical with that of conventional manual pull type hoists, they shall not be further described; however, the unique features of this embodiment are the same as those disclosed of the manual crank type hoist and includes an umbrella type gear ring 10, an elastic component 20, a drive sleeve 30, an adjustment nut 40, an equalizing washer 50, and a locating ring 60 in an insertional spatial arrangement that are respectively disposed at the axial end surfaces at the two sides of the drive component 7 hand chain wheel 7a.
Referring to FIG. 12, screws or rivets (not shown in the drawings) fasten the umbrella type gear ring 10 and the drive component 7 hand chain wheel 7a axially at the end surfaces to conjoin them into a single entity, and utilizing the drive sleeve 30 axially, the hollow neck 32 is inserted lengthwise through the hand chain wheel 7a and the umbrella type gear ring 10 and, furthermore, the elastic component 20, the equalizing washer 50, and the locating ring 60 are respectively and pivotally conjoined to the other lateral end of the hand chain wheel 7a and, finally, the adjustment nut 40 is similarly fastened tight onto the external threads 321 along the end of the drive sleeve 30 such that the drive component 7 hand chain wheel 7a, the elastic component 20, the drive sleeve 30, the equalizing washer 50, and the locating ring 60 are axially conjoined into a single entity; utilizing the adjustment nut 40 tightness to produce pressure against the drive component 7 and axially towards the hand chain wheel 7a, the equalizing washer 50 transfers balanced force against the elastic component 20, its changes in shape resulting in axial thrust that produces the required load torsion; since the structural components are insertionally conjoined such that the umbrella type gear ring 10 at the end surface of the drive component 7 hand chain wheel 7a is against the drive sleeve 30 umbrella type teeth section 311, as shown in FIG. 12, increasing the elastic component 20 force increases the lateral contact friction between the umbrella type gear ring 10 and the umbrella type teeth section 311, the hand chain wheel 7a required to transfer greater rotational torque before the onset of slippage, with the converse action requiring the transfer of less rotational torque before slippage; when the load pulley 2 at the emergent end of the transmission shaft 4 is subjected to a load that exceeds the set rotational torque, then the hand chain wheel 7a pulled and controlled by the hand chain wheel 7b slips to protect the inputted transfer from overload.
To continue, when no overload occurs during the transmission process, as indicated in FIG. 9, the land sections 311B and 12 engage perpendicularly to achieve forward rotation or, as indicated in FIG. 10, the umbrella type gear ring 10 and the umbrella type teeth section 311 two slanted facets 311A and 11 engage to achieve reverse operation, and the hand chain 7b pulls the transmission shaft 4 to draw a chain 6 mounted over the load pulley wheel 2 that is connected to the hoisting hook 6a coupled to a heavy object.
When an overload occurs during the transmission process, likewise, the umbrella type gear ring 10 and the umbrella type teeth section 311 two slanted facets 311A and 1I that were originally pushed and squeezed against each other are then impelled laterally to disengage the land sections 311B and 12, following which they fall into another engagement with the slanted facets 311A and 11 and, as a result, the umbrella type gear ring 10 and the umbrella type teeth section 311 slip apart and spin in neutral, thereafter manifesting a metallic frictional sound to inform the operator of the overload to ensure work safety.
Patent Grant
7344121
