US4073476A — Overhead crane with redundant safety features

Claim 1

Independent Claim 259 words

An overhead crane having a variable lifting capacity and redundant safety features comprising: (a) a frame (b) two substantially axially parallel hoist drums mounted on said frame, each drum having two separate ropes wound thereon with one end of each rope attached to its respective drum; (c) means for rotating said drums; (d) an upper sheave assembly mounted on said frame, associated with both of said drums; (e) a lower block assembly suspended from said frame which includes an upper block sheave assembly associated with one of said drums and a lower block sheave assembly associated with the other drum, said upper and lower block sheave assemblies being independent of each other; (f) an equalizer bar assembly mounted on said frame having the other ends of said ropes attached to the equalizer bar assembly; (g) a hook assembly, associated with said lower load block assembly, which includes a lower hook assembly associated with said lower block sheave assembly and an upper hook assembly associated with said upper block sheave assembly, each of said upper and lower hook assemblies capable of independently supporting a weight equal to a plant lifting capacity; and (h) means for connecting said upper and lower hook assemblies to provide said crane with a redundant plant lifting capacity and a construction lifting capacity in excess of said plant lifting capacity, whereby when said crane is supporting a weight equal to said plant lifting capacity, a failure in one of said hook assemblies will be overcome by the other hook assembly and the weight will remain supported.

Claim 2

Dependent Claim 259 words

An overhead crane having a variable lifting capacity and redundant safety features comprising: (a) a frame (b) two substantially axially parallel hoist drums mounted on said frame, each drum having two separate ropes wound thereon with one end of each rope attached to its respective drum; (c) means for rotating said drums; (d) an upper sheave assembly mounted on said frame, associated with both of said drums; (e) a lower block assembly suspended from said frame which includes an upper block sheave assembly associated with one of said drums and a lower block sheave assembly associated with the other drum, said upper and lower block sheave assemblies being independent of each other; (f) an equalizer bar assembly mounted on said frame having the other ends of said ropes attached to the equalizer bar assembly; (g) a hook assembly, associated with said lower load block assembly, which includes a lower hook assembly associated with said lower block sheave assembly and an upper hook assembly associated with said upper block sheave assembly, each of said upper and lower hook assemblies capable of independently supporting a weight equal to a plant lifting capacity; and (h) means for connecting said upper and lower hook assemblies to provide said crane with a redundant plant lifting capacity and a construction lifting capacity in excess of said plant lifting capacity, whereby when said crane is supporting a weight equal to said plant lifting capacity, a failure in one of said hook assemblies will be overcome by the other hook assembly and the weight will remain supported.

Claim 3

Dependent Claim 104 words

The crane of claim 1 wherein the means for rotating said drums comprises: a first drum rotation assembly which includes a first brake, a first hoist gearbox, and a first drum gearbox; the first drum rotation assembly being mounted on said frame and associated with one end of each of said drums; the first drum gearbox having power transmitted to it from said first hoist gearbox; and the first drum gearbox being provided with means for rotating said drums simultaneously or independently of one another, whereby if one of said drums becomes inoperative, the other drum will be rotated by the first drum gearbox.

Claim 4

Dependent Claim 117 words

The crane of claim 2 wherein the means for rotating said drums further comprises: a second drum rotation assembly which includes a second brake, a second hoist gearbox, and a second drum gearbox; the second drum rotation assembly being mounted on said frame and is associated with the ends of said drums which are opposite to the ends which said first rotation assembly is associated; the second drum gearbox having power transmitted to it from said second hoist gearbox; and the second drum gearbox being provided with means for rotating said drums simultaneously or independently of one another, whereby if one of said drums becomes inoperative, the other drum will be rotated by the second drum gearbox.

Claim 5

Dependent Claim 20 words

The crane of claim 3 wherein the first and second brakes are associated with said first and second hoist gearboxes.

Claim 6

Dependent Claim 142 words

The crane of claim 1 wherein said equalizer bar assembly comprises: a common equalizer bar pivotably mounted on the frame which compensates for any rotational speed or size deviations associated with the hoist drums; a first equalizer bar pivotably mounted to one end of said common equalizer bar and associated with the lower block sheave assembly to maintain the stability of said lower block sheave assembly; a second equalizer bar pivotably mounted to the other end of the common equalizer bar and associated with the upper block sheave assembly to maintain the stability of said upper block sheave assembly; and the first and second equalizer bars functioning independently of one another, whereby a failure affecting one of said equalizer bars and its associated block sheave assembly does not impair the functioning of the other equalizer bar and its associated block sheave assembly.

Claim 7

Dependent Claim 53 words

The crane of claim 5 wherein the common equalizer bar is pivotably mounted about an axis which is substantially parallel to the longitudinal axis of the hoist drums and the first and second equalizer bars are pivotably mounted about an axis which is substantially perpendicular to the longitudinal axis of the hoist drums.

Claim 8

Dependent Claim 89 words

The crane of claim 1 wherein: the upper hook assembly comprised of a first hook means having a first shaft mounted on it; the first shaft of the upper hook assembly being fixedly secured to said upper block sheave assembly; the lower hook assembly is comprised of a second hook means having a second shaft mounted on it; the second shaft of the lower hook assembly being fixedly secured to said lower block sheave assembly; and the longitudinal axes of said first and second shafts coinciding with one another.

Claim 9

Dependent Claim 27 words

The crane of claim 7 wherein: said first hook means is comprised of a lifting eye; and said second hook means is comprised of a sister hook.

Claim 10

Dependent Claim 44 words

The crane of claim 8 wherein the means for connecting the upper and lower hook assemblies comprises: a sister hook extension means which is associated with the sister hook; and a connection member for connecting said sister hook extension means and said lifting eye.

Claim 11

Dependent Claim 72 words

The crane of claim 9 wherein: the sister hook extension means is comprised of two plate members which are fixedly secured to the sister hook, thus forming a space between the two plate members; the connection member is comprised of a bushing; the lifting eye is disposed below the sister hook in the space between the two plate members; and the bushing passes through the two plate members and the lifting eye.

Claim 12

Dependent Claim 182 words

In an overhead crane comprising a frame and a hook assembly, extendable and retractable through a plurality of sheave assemblies, the improvement which comprises: a dual element hook adapted to support plural loads; two indenpendently reeved hoisting systems, each system independently engaging the dual element hook and each system capable of supporting and lifting a first load on said hook; the hoisting systems being adapted to operate in unison to provide redundant safety features when supporting and lifting said first load and when supporting and lifting a second load which is greater than said first load; said two independently reeved hoisting systems including a lower load block assembly suspended from said frame, the lower load block assembly having an upper block sheave assembly associated with one of the independently reeved hoisting systems and a lower block sheave assembly associated with the other independently reeved hoisting system, said upper and lower block sheave assemblies being independently supported from each other, and in engagement with said hook; and each independently reeved hoisting system includes an independent take-up means for extending and retracting said system.

Claim 13

Dependent Claim 182 words

In an overhead crane comprising a frame and a hook assembly, extendable and retractable through a plurality of sheave assemblies, the improvement which comprises: a dual element hook adapted to support plural loads; two indenpendently reeved hoisting systems, each system independently engaging the dual element hook and each system capable of supporting and lifting a first load on said hook; the hoisting systems being adapted to operate in unison to provide redundant safety features when supporting and lifting said first load and when supporting and lifting a second load which is greater than said first load; said two independently reeved hoisting systems including a lower load block assembly suspended from said frame, the lower load block assembly having an upper block sheave assembly associated with one of the independently reeved hoisting systems and a lower block sheave assembly associated with the other independently reeved hoisting system, said upper and lower block sheave assemblies being independently supported from each other, and in engagement with said hook; and each independently reeved hoisting system includes an independent take-up means for extending and retracting said system.

Claim 14

Dependent Claim 53 words

The crane of claim 11 wherein each independently reeved hoisting system further includes: an upper sheave assembly; at least two ropes reeved on said upper sheave and one of said block sheave assemblies; said take-up means having one of the ends of each rope attached to said take-up means; and an equalizer bar.

Claim 15

Dependent Claim 30 words

The crane of claim 12 wherein each take-up means comprises a hoist drum having said ropes wound thereon with one end of each of said ropes attached to the drum.

Claim 16

Dependent Claim 19 words

The crane of claim 13 wherein a first drum rotation assembly is associated with both of said take-up means.

Claim 17

Dependent Claim 96 words

The crane of claim 14 wherein said first drum rotation assembly comprises: a first brake, a first hoist gearbox, and a first drum gearbox; the first drum rotation assembly being mounted on said frame and associated with one end of each of said drums; the first drum gearbox having power transmitted to it from said first hoist gearbox; and the first drum gearbox being provided with means for rotating said drums simultaneously or independently of one another, whereby if one of said drums becomes inoperative, the other drum will be rotated by the first drum gearbox.

Claim 18

Dependent Claim 19 words

The crane of claim 15 wherein a second drum rotation assembly is associated with both of said take-up means.

Claim 19

Dependent Claim 108 words

The crane of claim 16 wherein said second drum rotation assembly comprises: a second brake, a second hoist gearbox, and a second drum gearbox; the second drum rotation assembly being mounted on said frame and is associated with the ends of said drums which are opposite to the ends which said first rotation assembly is associated; the second drum gearbox having power transmitted to it from said second hoist gearbox; and the second drum gearbox being provided with means for rotating said drums simultaneously or independently of one another, whereby if one of said drums becomes inoperative, the other drum will be rotated by the second drum gearbox.

Claim 20

Dependent Claim 20 words

The crane of claim 17 wherein said first and second brakes are associated with said first and second hoist gearboxes.

Claim 21

Dependent Claim 29 words

The crane of claim 12 wherein: the equalizer bar of each independent sheave system is pivotably mounted upon a common equalizer bar which is pivotably mounted on the frame.

Claim 22

Dependent Claim 72 words

The crane of claim 11 wherein the dual element hook comprises: a first hook means having a first shaft mounted on it; a second hook means having a second shaft mounted on it; the first shaft being fixedly secured to one of said independent sheave systems; the second shaft being fixedly secured to the other independent sheave system; and a longitudinal axes of said first and second shafts coinciding with one another.

Claim 23

Dependent Claim 27 words

The crane of claim 20 wherein said first hook means is comprised of a lifting eye and said second hook means is comprised of a sister hook.

Claim 24

Dependent Claim 50 words

The crane of claim 21 wherein said dual element hook is provided with means for connecting the first and second hook means comprising: a sister hook extension means which is associated with the sister hook; and a connection member for connecting said sister hook extension means and said lifting eye.

Claim 25

Dependent Claim 72 words

The crane of claim 22 wherein: the sister hook extension means is comprised of two plate members which are fixedly secured to the sister hook, thus forming a space between the two plate members; the connection member is comprised of a bushing; the lifting eye is disposed below the sister hook in the space between the two plate members; and the bushing passes through the two plate members and the lifting eye.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1981-02-13	1981-08-15	1982-02-14	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1985-02-13	1985-08-15	1986-02-14	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1989-02-13	1989-08-15	1990-02-14	$7700.00	Window Closed / Lapsed

Overhead crane with redundant safety features

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