Patent US3218375A successfully refreshed from Google Patents.
Patent US4027489A successfully refreshed from Google Patents.
US4027489A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mine roof support
Assignee: Dowty Mining Equipment Ltd
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Filing: 1976-04-12
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Granted: 1977-06-07
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Expires: 1996-04-12
Abstract
Abstract A mine roof support comprising a roof engaging canopy, a floor-engaging means, a pair of shields pivotally secured to the canopy and extending downwardly and rearwardly in side-by-side relation over the floor-engaging means, a quadrilateral linkage securing each shield to the floor-engaging means and extensible strut means for adjusting the height of the canopy so arranged that the canopy may tilt about a transverse horizontal axis and a fore and aft axis to engage the roof, the shields being capable of providing differing height settings to accommodate canopy tilt about the fore and aft axis.
Inventors
- 👤 John Hirst Walker
- 👤 James Anthony Sutton
- 👤 John Henry Waters
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 18:15
CPC Classifications
E; E21; E21D; E21D23/00; E21D23/03; E21D23/0004; E21D23/0034; E21D23/0039
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
110 words
A mine roof support comprising a floor engaging means, a roof engageable means above the floor engaging means, and interconnection between the floor engaging means and the roof engageable means, the interconnection including two shields in side-by-side relationship, a part of each shield being pivotally associated at the roof engageable means and being capable of movement in a heightwise direction relative to the corresponding part of the other shield, spring means for urging the shields into their side-by-side relation in which the said shield parts have the same height setting, and jack means adjustable in length to vary the height of the roof engageable means over the floor engaging means.
Claim 2
Dependent Claim
110 words
A mine roof support comprising a floor engaging means, a roof engageable means above the floor engaging means, and interconnection between the floor engaging means and the roof engageable means, the interconnection including two shields in side-by-side relationship, a part of each shield being pivotally associated at the roof engageable means and being capable of movement in a heightwise direction relative to the corresponding part of the other shield, spring means for urging the shields into their side-by-side relation in which the said shield parts have the same height setting, and jack means adjustable in length to vary the height of the roof engageable means over the floor engaging means.
Claim 3
Dependent Claim
52 words
A mine roof support as claimed in claim 1, wherein the roof engageable means comprises a single member and including a universal joint mounting the single member on each shield whereby the single member is tiltable about a fore and aft axis by virtue of the differing height settings between the shields.
Claim 4
Dependent Claim
22 words
A mine roof support as claimed in claim 1, wherein the shields are supported on the floor engaging means by pivot connections.
Claim 5
Dependent Claim
22 words
A mine roof support as claimed in claim 2, wherein the shields are supported on the floor engaging means by pivot connections.
Claim 6
Dependent Claim
47 words
A mine roof support as claimed in claim 3, wherein the pivot connections for each shield comprise an upper link and a lower link pivotally engaging the lower end portion of the shield at spaced positions and also pivotaly engaging the floor engaging means at spaced positions.
Claim 7
Dependent Claim
47 words
A mine roof support as claimed in claim 4, wherein the pivot connection for each shield comprises an upper link and a lower link pivotally engaging the lower end portion of the shield at spaced positions and also pivotally engaging the floor engaging means at spaced positions.
Claim 8
Dependent Claim
165 words
A mine roof support comprising a floor engaging means, a roof engageable means above the floor engaging means, an interconnection between the floor engaging means and the roof engageable means comprising two shields in side by side relationship, a part of each shield being pivotally associated with the roof engageable means and being capable of movement in a heightwise direction relative to the corresponding part of the other shield, jack means adjustable in length to vary the height of the roof engageable means over the floor engaging means, spring means for urging the shields into their side by side relation, in which the shield parts have the same height setting and for each shield an upper link and a lower link pivotally engaging the lower end portion of the shield at spaced positions and also pivotally engaging the floor engaging means at spaced positions, the said spring means including a first spring acting in between the two upperlinks to hold them in spaced parallel relation.
Claim 9
Dependent Claim
165 words
A mine roof support comprising a floor engaging means, a roof engageable means above the floor engaging means, an interconnection between the floor engaging means and the roof engageable means comprising two shields in side by side relationship, a part of each shield being pivotally associated with the roof engageable means and being capable of movement in a heightwise direction relative to the corresponding part of the other shield, jack means adjustable in length to vary the height of the roof engageable means over the floor engaging means, spring means for urging the shields into their side by side relation, in which the shield parts have the same height setting and for each shield an upper link and a lower link pivotally engaging the lower end portion of the shield at spaced positions and also pivotally engaging the floor engaging means at spaced positions, the said spring means including a first spring acting in between the two upperlinks to hold them in spaced parallel relation.
Claim 10
Dependent Claim
53 words
A mine roof support as claimed in claim 7, wherein the roof engageable means comprises a single member and including a universal joint mounting the single member on each shield, whereby the single member is tiltable about a fore and aft axis by virtue of the differing height settings between the shield parts.
Claim 11
Dependent Claim
49 words
A mine roof support as claimed in claim 7, wherein the floor engaging means includes two spaced parallel beams extending in the fore and aft direction and the said spring means includes a second spring acting between the beams to tend to retain them in their spaced parallel relation.
Claim 12
Dependent Claim
49 words
A mine roof support as claimed in claim 8, wherein the floor engaging means includes two spaced parallel beams extending in the fore and aft direction, and the said spring means includes a second spring acting between the beams to tend to retain them in their spaced parallel relation.
References Cited (Backward Citations)
SU156132A1
Cited
GB1061071A
Cited
FR1482298A
Cited
DE1958322A1
Cited
DE2128023A1
Cited
US3921409A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-06-06 | 1980-12-06 | 1981-06-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-06-06 | 1984-12-06 | 1985-06-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-06-06 | 1988-12-06 | 1989-06-07 | $7700.00 | Window Closed / Lapsed |