Patent US3598200A successfully refreshed from Google Patents.
US3598200A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Extensible safety appliance for manhole ladders
Assignee: MEYER Manufacturing Inc
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Filing: 1970-07-09
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Granted: 1971-08-10
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Expires: 1990-07-09
Abstract
Abstract A sleeve attached to the rungs of a manhole ladder has a slidable rod therein which is extendable upward from the manhole to provide a vertical railing for workman on the ladder. A support at the lower end of the rod releasably engages a ladder rung to retain the rod in extended position; when unneeded the rod can be stored wholly within the manhole. The purpose of the foregoing abstract is to enable the Patent Office and the public generally, and especially the scientists, engineers, or practitioners in the art who are not familiar with patent or legal terms of phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by claims, nor is it intended to be limiting as to the scope of the invention in any way.
Inventors
- 👤 Harvey L Thompson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:27
CPC Classifications
E; E06; E06C; E06C7/00; E06C7/18; E06C7/186
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
135 words
An extensible safety appliance for attachment to the rungs of a manhole ladder comprising: a rigid sleeve attached to the ladder; a rigid rod slidable in the sleeve, the upper end of the rod being accessible to an operator outside the manhole so the operator can pull the rod upward out of the manhole so as to form a vertical railing to grasp when on the ladder and so the rod can be slid downward in the manhole when unneeded; a support swingably mounted to the lower end of the rod, the support including a downwardly opening notch to receive a ladder rung therein thus supporting the rod; and means on the support alternately obstructing and opening the notch to permit lowering of the rod past successive ladder rungs by an operator outside the manhole.
Claim 2
Dependent Claim
135 words
An extensible safety appliance for attachment to the rungs of a manhole ladder comprising: a rigid sleeve attached to the ladder; a rigid rod slidable in the sleeve, the upper end of the rod being accessible to an operator outside the manhole so the operator can pull the rod upward out of the manhole so as to form a vertical railing to grasp when on the ladder and so the rod can be slid downward in the manhole when unneeded; a support swingably mounted to the lower end of the rod, the support including a downwardly opening notch to receive a ladder rung therein thus supporting the rod; and means on the support alternately obstructing and opening the notch to permit lowering of the rod past successive ladder rungs by an operator outside the manhole.
Claim 3
Dependent Claim
55 words
The combination according to claim 1 wherein a handle assembly is formed at the upper end of the rod so the rod is readily accessible to an operator outside the manhole, the handle assembly resting on the upper end of the sleeve and wholly within the manhole when said rod is stored in the manhole.
Claim 4
Dependent Claim
30 words
The combination according to claim 2 wherein a safety cable is attached to said handle assembly and a cable-gripping clamp attachable to a safety belt is carried on the cable.
Claim 5
Dependent Claim
47 words
The combination according to claim 1 wherein said means on the support alternately obstructing and opening the notch includes a closure swingably mounted to the support to obstruct the notch when in a closed position and to swing clear of the notch when in an open position.
Claim 6
Dependent Claim
65 words
The combination according to claim 4 wherein: the closure is arranged on the support such that the closure when in open position contacts successive rungs of the ladder as the support is lowered and each contacting rung moves the closure to a closed position thus permitting the rod and support to be lowered wholly into the manhole for storage without the support engaging a rung.
Claim 7
Dependent Claim
273 words
An extensible safety appliance for attachment to the rungs of a manhole ladder comprising: a rigid sleeve attached to the ladder; a rigid rod slideable in said sleeve, the upper end of said rod being accessible to an operator outside the manhole so the operator can pull the rod upward out of the manhole so as to form a vertical railing to grasp when on the ladder and so the rod can be slid downward wholly within the manhole when unneeded; a support swingably mounted to the lower end of the rod, the support including a downwardly opening notch and the support having a closure swingably mounted thereto to obstruct the notch when in a closed position and to swiNg clear of the notch when in an open position; the notch of the support engageable with a ladder rung by pulling the rod and support upward until the notch is above and the closure below a given rung and then lowering the notch into engagement with the given rung thus retaining the rod and support in an upright extending position on the ladder to form a vertical railing by cooperation between support, rod, and sleeve; the support disengageable from the given rung by pulling the rod upward sufficiently to raise the closure above the rung; and the closure arranged on the support such that the closure when in open position contacts successive rungs of the ladder as the support is lowered and each contacting rung moves the closure to a closed position thus permitting the rod and support to be lowered wholly into the manhole for storage without the support engaging a rung.
Claim 8
Dependent Claim
273 words
An extensible safety appliance for attachment to the rungs of a manhole ladder comprising: a rigid sleeve attached to the ladder; a rigid rod slideable in said sleeve, the upper end of said rod being accessible to an operator outside the manhole so the operator can pull the rod upward out of the manhole so as to form a vertical railing to grasp when on the ladder and so the rod can be slid downward wholly within the manhole when unneeded; a support swingably mounted to the lower end of the rod, the support including a downwardly opening notch and the support having a closure swingably mounted thereto to obstruct the notch when in a closed position and to swiNg clear of the notch when in an open position; the notch of the support engageable with a ladder rung by pulling the rod and support upward until the notch is above and the closure below a given rung and then lowering the notch into engagement with the given rung thus retaining the rod and support in an upright extending position on the ladder to form a vertical railing by cooperation between support, rod, and sleeve; the support disengageable from the given rung by pulling the rod upward sufficiently to raise the closure above the rung; and the closure arranged on the support such that the closure when in open position contacts successive rungs of the ladder as the support is lowered and each contacting rung moves the closure to a closed position thus permitting the rod and support to be lowered wholly into the manhole for storage without the support engaging a rung.
Claim 9
Dependent Claim
103 words
An extensible safety appliance for attachment to the rungs of a manhole ladder comprising: a rigid sleeve attached to the ladder; a rigid rod slidable in the sleeve, the upper end of the rod being accessible to an operator outside the manhole so the operator can pull the rod upward out of the manhole so as to form a vertical railing to grasp when on the ladder and so the rod can be slid downward in the sleeve to rest wholly within the manhole when unneeded; and means at the lower end of the rod for supporting the rod on a ladder rung.
Claim 10
Dependent Claim
103 words
An extensible safety appliance for attachment to the rungs of a manhole ladder comprising: a rigid sleeve attached to the ladder; a rigid rod slidable in the sleeve, the upper end of the rod being accessible to an operator outside the manhole so the operator can pull the rod upward out of the manhole so as to form a vertical railing to grasp when on the ladder and so the rod can be slid downward in the sleeve to rest wholly within the manhole when unneeded; and means at the lower end of the rod for supporting the rod on a ladder rung.
Claim 11
Dependent Claim
28 words
The combination according to claim 7 wherein the supporting means is a downwardly opening notch in the lower end of the rod constructed to releasably receive the rung.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-08-09 | 1975-02-08 | 1975-08-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-09 | 1979-02-08 | 1979-08-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-09 | 1983-02-08 | 1983-08-10 | $7700.00 | Window Closed / Lapsed |