Patent Grant
8201810
1. Field of the Invention
The present invention relates to hoists and more particularly to hoists including a backbone and a rotating, cable-wound drum.
2. Description of the Related Art
One conventional type of hoist includes a cable that is wound and unwound from a drum to move a load. An example of such a hoist is shown as hoist system 100 in
In system 100: (i) the end bearing assembly (including the third bearing) is very rigidly and precisely located in space; (ii) the reducer (including the first and second bearings) is very rigidly and precisely located in space; and (iii) the shaft is made to be precisely co-axial with axis A1. Because of this precision and rigidity, the system works well. Unfortunately, it has been recognized that it is difficult to make all the components of system 100 so that they exhibit the precision and rigidity required for smooth operation. If there are variation from the above-noted types of precision and/or rigidity identified in this paragraph, then the shaft may be influenced to bend, as shown (in an exaggerated manner) by curved axis A2. If the shaft is bent, or stressed to bend by the bearings, in the bent direction of axis A2, then stresses and strains will cause, wear, damage and/or failure of the components of system 100. System 100 will not work well when the shaft is bent or stressed in the bending direction. As an example of the issues involved in giving system 100 the requisite degree of rigidity and precision, the backbone is precisely manufactured of very rigid material. As a further example of the issues involved in giving system 100 the requisite degree of rigidity and precision, reducer connecting hardware set 105 must rigidly and precisely connect the reducer, as well as bearings 112 and 114, to the backbone.
Because of the difficulty and/or expense in manufacturing hoist system components with the requisite degree of rigidity and/or precision, some conventional systems allow the bearings that constrain the shaft to have certain degrees (or directions) and quanta of freedom of motions. One conventional example, shown in
In shaft mounting hoist system 200, the reducer connecting hardware set connects the reducer assembly to the backbone so that degrees and freedom/constraint are determined with respect to a constraint point (see DEFINITIONS section). More specifically, the constraint point has the following degrees of freedom/constraint, relative to the backbone: (i) free in along X; (ii) free in rotation about X; (iii) fixed in along Y; (iv) free in rotation about Y; (v) free in along Z; and (vi) free in rotation about Z. In other words, the reducer connecting hardware set is further structured so that the constraint point is only rigidly constrained (relative to the backbone) in the along-Y direction, and this constraint point must be offset from the axis of rotation in the along-X direction. Alternatively, the sole direction of constraint can be in a different direction, such as along-X, but the important thing to keep in mind is that there is only a single direction of tension/compression type constraint. The constraint point in the shaft mounting type hoist design is otherwise free to move relative to the backbone.
In the shaft mounting type hoist design, the pillow block bearings (see DEFINITIONS section) each place the following degrees of freedom/constraint on shaft 208: (i) fixed in along X; (ii) free in rotation about X; (iii) fixed in along Y; (iv) free in rotation about Y; (v) fixed in along Z; and (vi) free in rotation about Z. preferably bearings 212 and 214 are “rigid bearings” (see DEFINITIONS section).
Because of the above-identified distribution of degrees of freedom/constraint in the reducer constraint point and on shaft at the locations of the pillow bearings, the shaft mounting type hoist system 200 is free to move so it can accommodate some shaft bending (see
Another conventional hoist system is shown in U.S. Pat. No. 4,796,862 (“Peppel”). The Peppel winch includes a pillow block bearing 30 which allows the shaft some degree of freedom of motion with respect to its axis. This is another way to reduce the requisite degree of rigidity and precision of components when making and assembling a hoist.
Other publications which may be of interest may include the following: (i) pillow bock bearing Wikipedia entry (http://e.wikipedia.org/wiki/Pillow_block_bearing as of May 5, 2009); (ii) U.S. Pat. No. 6,089,547 (“Juelich”); and/or (iii) U.S. Pat. No. 5,921,529 (“Wilson”).
Description of the Related Art Section Disclaimer: To the extent that specific publications are discussed above in this Description of the Related Art Section, these discussions should not be taken as an admission that the discussed publications (for example, published patents) are prior art for patent law purposes. For example, some or all of the discussed publications may not be sufficiently early in time, may not reflect subject matter developed early enough in time and/or may not be sufficiently enabling so as to amount to prior art for patent law purposes. To the extent that specific publications are discussed above in this Description of the Related Art Section, they are all hereby incorporated by reference into this document in their respective entirety(ies).
According to the present invention, a hoist system includes at least two spaced apart bearings that are supported by a frame. The bearings support a rotating shaft segment. One of the bearings is a pillow block bearing that is rigidly connected to the frame (either directly or through intermediate hardware). The other bearing is part of a bearing assembly that is connected to the frame by assembly connection hardware. The assembly connection hardware is shaped, sized, located and/or connected so that it supports the bearing assembly (including its bearing(s)) in a way that has certain, carefully chosen, degrees of freedom and constraint. These degrees of constraint are defined with respect to a first and a second “constraint point” (see DEFINITIONS section). More specifically, the assembly connection hardware is sized, shaped, located and/or connected so that the first constraint point and the second constraint point have the following degrees of freedom and constraint: (i) first constraint point fixed or free in along X (see
As an alternative way of looking at or defining the kinematics of hoists according to the present invention the assembly connection hardware is sized, shaped, located, and/or connected such that it will transmit, from the bearing assembly to the frame, forces parallel with the X axis, forces parallel with the Y axis, and moments about the Z axis. The mechanism will not transmit forces in the Z direction, moments about the X axis, or moments about the Y axis. Note that by fixing the X and Y translational degrees of freedom the assembly connection hardware can provide sufficient stability for the shaft and the bearing assembly. Also, by fixing moments about the Z axis it transmits to the frame the torsion due to the lifted load of the hoist. However, by not fixing the X and Y rotational degrees of freedom the bearing assembly is free to rotate to accommodate deviations in the straightness of the shaft caused by manufacturing imperfections or deflection due to loading. Furthermore, by not fixing these degrees of freedom the requirements for manufacturing precision required to mount the shaft and bearing assembly are reduced and the forces imposed on the shaft may be more accurately predicted.
Various embodiments of the present invention may exhibit one or more of the following objects, features and/or advantages:
(i) less expensive hoist assembly;
(ii) more durable hoist assembly;
(iii) hoist assembly that better accommodates for a bent shaft or shaft segment; and/or
(iv) hoist assembly that better accommodates for slight misalignment of coaxial bearings.
According to one aspect of the present invention, a hoist system defines X, Y and Z directions. The system includes: a frame, a first shaft segment, a first bearing assembly, a first-assembly connection hardware set and a second bearing assembly. The first bearing assembly is mechanically connected to the frame by the first-assembly connection hardware set. The first bearing assembly comprises a first bearing. The second bearing assembly is rigidly mechanically connected to the frame. The second bearing assembly comprises a second bearing located to be spaced apart from the first bearing. The second bearing is a pillow block bearing. The first bearing and the second bearing are shaped, sized and located to support and constrain the first shaft segment so that the first shaft segment is free to rotate about the Z direction. The first-assembly connection hardware set defines a first constraint point and a second constraint point spaced apart from the first constraint point. The first-assembly connection hardware set is sized, shaped, located and/or connected so that the first bearing assembly has, relative to the frame and with respect to the first constraint point, the following degrees of freedom/constraint: (i) fixed or free in along X; (ii) free in rotation about X; (iii) fixed in along Y; (iv) free in rotation about Y; (v) free in along Z; (vi) free in rotation about Z. The first-assembly connection hardware set is further sized, shaped, located and/or connected so that the first bearing assembly has, relative to the frame and with respect to the second constraint point, the following degrees of freedom/constraint: (i) fixed in along X; (ii) free in rotation about X; (iii) fixed in along Y; (iv) free in rotation about Y; (v) free in along Z; and (vi) free in rotation about Z.
According to a further aspect of the present invention, a hoist system defines X, Y and Z directions. The system includes: a frame, a first shaft segment, a first bearing assembly, a first-assembly connection hardware set, a second bearing assembly, a second shaft segment and a shaft coupling hardware set. The first bearing assembly is mechanically connected to the frame by the first-assembly connection hardware set. The first bearing assembly comprises a first bearing. The second bearing assembly is rigidly mechanically connected to the frame. The second bearing assembly comprises a second bearing located to be spaced apart from the first bearing. The second bearing is a pillow block bearing. The first bearing and the second bearing are shaped, sized and located to support and constrain the first shaft segment so that the first shaft segment is free to rotate about the Z direction. The first-assembly connection hardware set defines a first constraint point and a second constraint point spaced apart from the first constraint point. The first-assembly connection hardware set is sized, shaped, located and/or connected so that the first bearing assembly has, relative to the frame and with respect to the first constraint point, the following degrees of freedom/constraint: (i) fixed or free in along X; (ii) free in rotation about X; (iii) fixed in along Y; (iv) free in rotation about Y; (v) free in along Z; and (vi) free in rotation about Z. The first-assembly connection hardware set is further sized, shaped, located and/or connected so that the first bearing assembly has, relative to the frame and with respect to the second constraint point, the following degrees of freedom/constraint: (i) fixed in along X; (ii) free in rotation about X; (iii) fixed in along Y; (iv) free in rotation about Y; (v) free in along Z; and (vi) free in rotation about Z. The shaft coupling hardware set couples the first shaft segment and the second shaft segment so that they rotate together about the Z direction. The shaft coupling hardware transmits only radial loads and loads in torsion.
According to a further aspect of the present invention, a hoist system defines X, Y and Z directions, the system includes: a backbone, a motor, a hoist hardware set, a first shaft segment, a motor-end bearing assembly, a motor-end-assembly connection hardware set and a pillow block bearing assembly. The hoist hardware set is mechanically connected to an end of the first shaft segment. The motor is rigidly mechanically connected to the motor end bearing assembly. The motor is structured, located and/or connected to drive the first shaft segment to rotate about Z. The motor-end bearing assembly is mechanically connected to the backbone by the motor-end-assembly connection hardware set. The motor-end bearing assembly comprises a first motor-end bearing and a second motor-end bearing. The intermediate bearing assembly is rigidly mechanically connected to the backbone. The intermediate bearing assembly comprises a pillow block bearing located to be spaced apart from, and at least substantially co-axial with, the first motor end-end bearing and the second motor-end bearing. The pillow block bearing, the first motor-end bearing and the second motor-end bearing are shaped, sized and located to support and constrain the first shaft segment so that the first shaft segment is free to rotate about the Z direction. The motor-end-assembly connection hardware set defines a first constraint point and a second constraint point spaced apart from the first constraint point. The motor-end-assembly connection hardware set is sized, shaped, located and/or connected so that the motor-end bearing assembly has, relative to the backbone and with respect to the first constraint point, the following degrees of freedom/constraint: (i) fixed or free in along X; (ii) free in rotation about X; (iii) fixed in along Y; (iv) free in rotation about Y; (v) free in along Z; and (vi) free in rotation about Z. The motor-end-assembly connection hardware set is further sized, shaped, located and/or connected so that the first bearing assembly has, relative to the backbone and with respect to the second constraint point, the following degrees of freedom/constraint: (i) fixed in along X; (ii) free in rotation about X; (iii) fixed in along Y; (iv) free in rotation about Y; (v) free in along Z; and (vi) free in rotation about Z.
According to a further aspect of the present invention, a hoist system defines X, Y and Z directions. The system includes: a frame, a first shaft segment, a first bearing assembly, a first-assembly connection hardware set and a second bearing assembly. The first bearing assembly is mechanically connected to the frame by the first-assembly connection hardware set. The first bearing assembly comprises a first bearing. The second bearing assembly is rigidly mechanically connected to the frame. The second bearing assembly comprises a second bearing located to be spaced apart from the first bearing. The second bearing is a pillow block bearing. The first bearing and the second bearing are shaped, sized and located to support and constrain the first shaft segment so that the first shaft segment is free to rotate about the Z direction. The first-assembly connection hardware set defines a first constraint point and a second constraint point spaced apart from the first constraint point. The first-assembly connection hardware set is sized, shaped, located and/or connected so that such that it will transmit, from the first bearing assembly to the frame, forces parallel with the X axis, forces parallel with the Y axis, and moments about the Z axis. The first-assembly connection hardware set is further sized, shaped, located and/or connected so that such that it will not transmit forces in the Z direction, moments about the X axis, or moments about the Y axis.
According to a further aspect of the present invention, a method of hoisting an object includes the following steps i, ii, etc. (not necessarily in the following order): (i) providing a hoist system defining X, Y and Z directions, the system including: a frame, a first shaft segment, a first bearing assembly, a first-assembly connection hardware set and a second bearing assembly, wherein: (a) the first bearing assembly is mechanically connected to the frame by the first-assembly connection hardware set, (b) the first bearing assembly comprises a first bearing, (c) the second bearing assembly is rigidly mechanically connected to the frame, (d) the second bearing assembly comprises a second bearing located to be spaced apart from the first bearing, (e) the second bearing is a pillow block bearing, (f) the first bearing and the second bearing are shaped, sized and located to support and constrain the first shaft segment so that the first shaft segment is free to rotate about the Z direction, and (g) the first-assembly connection hardware set defines a first constraint point and a second constraint point spaced apart from the first constraint point; (ii) hoisting a load so that: (a) the first constraint point is free in rotation about X; (b) the first constraint point is fixed in along Y; (c) the first constraint point is free in rotation about Y; (d) the first constraint point is free in along Z; (e) the first constraint point is free in rotation about Z; (f) the second constraint point is fixed in along X; (g) the second constraint point is free in rotation about X; (h) the second constraint point is fixed in along Y; (i) the second constraint point is free in rotation about Y; (j) the second constraint point is free in along Z; and (k) the second constraint point is free in rotation about Z.
The present invention will be more fully understood and appreciated by reading the following Detailed Description in conjunction with the accompanying drawings, in which:
One important aspect of the kinematic mount of system 300 is its pillow block, and another aspect is its first connection hardware set. The pillow block will be discussed first. Pillow block 311 may be any type of pillow block now known or to be developed in the future. The pillow block constrains one end of rotating shaft segment 308, specifically the end where it is coupled to second shaft segment 309 by shaft coupling hardware set 330. More particularly,
Motor-end bearing assembly 310 is mechanically connected to the backbone by first connection hardware set 305, which provides certain degrees of freedom/constraint with respect to two constraint points, as will now be discussed. As shown in
In system 300, the motor-end bearing assembly itself is rigid. Preferably, it helps serve as a housing for a reducer hardware set (not shown) and as a mounting bracket for motor 306. Preferably, first motor-end bearing and second motor-end bearing are rigid bearings, but this is not necessarily required. Also, some embodiments of the present invention may have a single bearing in the motor end bearing assembly. As a further variation, the kinematically-optimized constraints used in the motor-end assembly do not necessarily need to be at the motor end of the hoist—indeed some embodiments of the present invention may not have a motor at all. For example, the drum-end bearing assembly 322 could be kinematically mounted instead of (or in addition to) the motor-end bearing assembly.
Shaft coupling hardware set 330 couples shaft segments 308 and 309 so that these shaft segments rotate together. More specifically, the shaft coupling hardware set transmits loads in torsion and radial loads, but is otherwise allows relative motion between the ends of the shaft segments 308 and 309. In a variation on system 300, the drum-end bearing could be replaced with a pillow block and the intermediate bearing assembly and the shaft coupling hardware could be omitted so that a single shaft segment is used. System 300 is a shaft that uses a cable-wound drum as its hoist hardware, but other embodiments may use other types of rotating hoist hardware, such as chain-and-sprocket type hoist hardware.
The intermediate bearing assembly and its pillow block bearing provide similar freedom and constrain to shaft constraint point L (see
Motor-end connection hardware set 505 will now be discussed. Generally speaking, motor-end connection hardware set 505 is structured, located and connected to provide similar freedom and constraint for the motor-end bearing assembly (with respect to constraint points M and N) as motor-end connection hardware set 305, discussed above in connection with system 300. Kinematically speaking, the one variation, is that the use of bracket piece shown in
As best shown in
As shown in
As best shown in
As shown in
The following definitions are provided to facilitate claim interpretation:
Present invention: means at least some embodiments of the present invention; references to various feature(s) of the “present invention” throughout this document do not mean that all claimed embodiments or methods include the referenced feature(s).
First, second, third, etc. (“ordinals”): Unless otherwise noted, ordinals only serve to distinguish or identify (e.g., various members of a group); the mere use of ordinals implies neither a consecutive numerical limit nor a serial limitation.
Mechanically connected: Includes both direct mechanical connections, and indirect mechanical connections made through intermediate components; includes rigid mechanical connections as well as mechanical connection that allows for relative motion between the mechanically connected components; includes, but is not limited, to welded connections, solder connections, connections by fasteners (for example, nails, bolts, screws, nuts, hook-and-loop fasteners, knots, rivets, force fit connections, friction fit connections, connections secured by engagement added by gravitational forces, quick-release connections, pivoting or rotatable connections, slidable mechanical connections, latches and/or magnetic connections).
Rigid: at least substantially rigid, but not necessarily ideally rigid.
Rigidly mechanically connected: a mechanical connection (see DEFINITIONS section) that is rigid (see DEFINITIONS section) with respect to all six (60 degrees of freedom/constraint.
Receive/provide/send/input/output: unless otherwise explicitly specified, these words should not be taken to imply: (i) any particular degree of directness with respect to the relationship between their objects and subjects; and/or (ii) absence of intermediate components, actions and/or things interposed between their objects and subjects.
X-direction, Y-direction, Z-direction: are defined by the shaft and backbone or frame of a hoist substantially as shown in
Constraint points: are defined by the shape of mechanical interfaces that provide relative restraint; a constraint point does not necessarily lie inside the body of the component or assembly for which it is defined.
Pillow block bearing: any hardware for supporting a rotating shaft segment so that it has the following degrees of freedom/constraint: (i) along-X (see
Rigid bearing: a bearing that is rigid (see definitions section) in all directions except: (i) it allows rotation of the shaft about Z; and (ii) it may or may not allow the shaft to move in the along-Z direction.
Bearing: includes, but is not necessarily limited to, pillow block type bearings (see DEFINITIONS section) and rigid type bearings (see DEFINITIONS section).
Frame: frames include but are not limited to frames in the form of a backbone.
To the extent that the definitions provided above are consistent with ordinary, plain, and accustomed meanings (as generally shown by documents such as dictionaries and/or technical lexicons), the above definitions shall be considered supplemental in nature. To the extent that the definitions provided above are inconsistent with ordinary, plain, and accustomed meanings (as generally shown by documents such as dictionaries and/or technical lexicons), the above definitions shall control. If the definitions provided above are broader than the ordinary, plain, and accustomed meanings in some aspect, then the above definitions shall be considered to broaden the claim accordingly.
To the extent that a patentee may act as its own lexicographer under applicable law, it is hereby further directed that all words appearing in the claims section, except for the above-defined words, shall take on their ordinary, plain, and accustomed meanings (as generally shown by documents such as dictionaries and/or technical lexicons), and shall not be considered to be specially defined in this specification. In the situation where a word or term used in the claims has more than one alternative ordinary, plain and accustomed meaning, the broadest definition that is consistent with technological feasibility and not directly inconsistent with the specification shall control.
Unless otherwise explicitly provided in the claim language, steps in method steps or process claims need only be performed in the same time order as the order the steps are recited in the claim only to the extent that impossibility or extreme feasibility problems dictate that the recited step order (or portion of the recited step order) be used. This broad interpretation with respect to step order is to be used regardless of whether the alternative time ordering(s) of the claimed steps is particularly mentioned or discussed in this document.
The present application claims priority to U.S. provisional patent application No. 61/160,885, filed on Mar. 17, 2009; all of the foregoing patent-related document(s) are hereby incorporated by reference herein in their respective entirety(ies).
| Number | Name | Date | Kind |
|---|---|---|---|
| 4191316 | Baumgartner | Mar 1980 | A |
| 4493479 | Clark | Jan 1985 | A |
| 4796862 | Peppel | Jan 1989 | A |
| 5615864 | Liebetrau et al. | Apr 1997 | A |
| 5921529 | Wilson, Sr. et al. | Jul 1999 | A |
| 5947639 | Bishop et al. | Sep 1999 | A |
| 6089547 | Juelich et al. | Jul 2000 | A |
| 7090200 | Morse et al. | Aug 2006 | B2 |
| 7545517 | Rueb et al. | Jun 2009 | B2 |
| 7591624 | Campbell et al. | Sep 2009 | B2 |
| 8085482 | Frankovich et al. | Dec 2011 | B2 |
| Number | Date | Country |
|---|---|---|
| 005329 | Jun 1982 | EP |
| 2019870000803 | Feb 1987 | KR |
| Number | Date | Country | |
|---|---|---|---|
| 20100237304 A1 | Sep 2010 | US |
| Number | Date | Country | |
|---|---|---|---|
| 61160885 | Mar 2009 | US |
