US3793752A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Convertible snow plow with auxiliary ground support
Assignee: SCHMIDT ENGINEERING & EQUIPMENT Co A CORP OF
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Filing: 1972-12-29
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Granted: 1974-02-26
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Expires: 1992-12-29
Abstract
Abstract A snow plow attachable to the front of a truck or other vehicle. A moldboard assembly is supported by hydraulic jacks on groundengaging members such as caster wheels or shoes and is connected by a thrust frame to a hitch on the vehicle. A moldboard has two separate blades each having a ground-engageable scraping edge. One blade is steel, fixed along the lower portion of the moldboard. The other blade is rubber-like and is movable to an extended, working position below the steel blade, enabling it to act as a squeegee to clear soft snow and slush. The rubber-like blade is also movable to a stowed position above the scraping edge of the steel blade, enabling the steel blade to engage the ground when a harder, general purpose cutting edge is required. Pressure applied to the hydraulic jacks exerts a lifting force on the moldboard assembly through the ground-engaging members. Pressure is regulated by a relief valve which is adjustable to transfer a definite, predetermined portion of the moldboard assembly weight to the ground-engaging members. By adjusting the relief valve, heavy cutting pressure, or light squeegee pressure, may be applied through the moldboard assembly as required by the steel or rubber-like blade.
Inventors
- 👤 R Snyder
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 18:48
CPC Classifications
E; E01; E01H; E01H5/00; E01H5/04; E01H5/06; E01H5/063
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
310 words
A Convertible snow plow comprising: a moldboard assembly including a moldboard having first and second blades, each having a scraping edge selectively engageable with the ground; said first blade being rigid and fixed along the lower portion of said moldboard; said second blade being rubber-like and mounted on said moldboard for movement between extended and retracted positions in which the scraping edge of the second blade is respectively below and above the scraping edge of the first blade; means for moving said second blade between said extended and retracted positions and for holding said second blade selectively in one of said positions; said moldboard assembly having horizontal pivotal connecting means on an axis transverse to the longitudinal centerline and spaced to the rear of said moldboard enabling attachment to a vehicle for up and down tilting adjustment of the moldboard assembly relative to the vehicle about said pivotal connecting means; hydraulic jacks mounted between the moldboard and the pivotal connecting means at opposite sides of the longitudinal centerline of the moldboard assembly and having groundcontacting supporting elements vertically movable to elevate the moldboard in response to flow of pressure fluid to said jacks; hydraulic control circuit means including a pump connected with said jacks through control valve means for directing fluid under pressure to said jacks to thereby exert a lifting force on the moldboard assembly through said ground-contacting supporting elements; and relief valve means connected with said jacks effective to limit the pressure supplied to said jacks to a value transferring a definite, predetermined portion less than the total of the weight of the moldboard assembly to said ground-contacting supporting elements, thereby limiting the weight of the moldboard assembly supported by either of said first or second blades in accordance with the pressure rating of said relief valve means while maintaining said blade in operative engagement with the ground.
Claim 2
Dependent Claim
310 words
A Convertible snow plow comprising: a moldboard assembly including a moldboard having first and second blades, each having a scraping edge selectively engageable with the ground; said first blade being rigid and fixed along the lower portion of said moldboard; said second blade being rubber-like and mounted on said moldboard for movement between extended and retracted positions in which the scraping edge of the second blade is respectively below and above the scraping edge of the first blade; means for moving said second blade between said extended and retracted positions and for holding said second blade selectively in one of said positions; said moldboard assembly having horizontal pivotal connecting means on an axis transverse to the longitudinal centerline and spaced to the rear of said moldboard enabling attachment to a vehicle for up and down tilting adjustment of the moldboard assembly relative to the vehicle about said pivotal connecting means; hydraulic jacks mounted between the moldboard and the pivotal connecting means at opposite sides of the longitudinal centerline of the moldboard assembly and having groundcontacting supporting elements vertically movable to elevate the moldboard in response to flow of pressure fluid to said jacks; hydraulic control circuit means including a pump connected with said jacks through control valve means for directing fluid under pressure to said jacks to thereby exert a lifting force on the moldboard assembly through said ground-contacting supporting elements; and relief valve means connected with said jacks effective to limit the pressure supplied to said jacks to a value transferring a definite, predetermined portion less than the total of the weight of the moldboard assembly to said ground-contacting supporting elements, thereby limiting the weight of the moldboard assembly supported by either of said first or second blades in accordance with the pressure rating of said relief valve means while maintaining said blade in operative engagement with the ground.
Claim 3
Dependent Claim
93 words
A convertible snow plow according to claim 1 having additional hydraulic jacks connected between said moldboard and said second blade, and said hydraulic control circuit means includes additional control valve means movable to two operative positions for directing fluid under pressure selectively to opposite ends of said additional jacks for moving said second blade between said extended and retracted positions, said additional control valve means being actuatable to an OFF position blocking the flow of fluid from said additional jacks to hold said second blade selectively in its said extended and retracted positions.
Claim 4
Dependent Claim
37 words
A convertible snow plow according to claim 1 in which said second blade is supported at the rear of said moldboard by a horizontal pivotal mounting and is vertically swingable between its said extended and retracted positions.
Claim 5
Dependent Claim
100 words
A convertible snow plow according to claim 3 having additional hydraulic jacks connected between said moldboard and said second blade, and said hydraulic control circuit means includes additional control valve means movable from an OFF position to either of two ON positions for selectively directing fluid under pressure to opposite ends of said additional jacks for moving said second blade to said extended and retracted positions, said additional valve means being effective in said OFF position to block the back flow of fluid from said additional jack means to hold said second blade selectively in either extended or retracted position.
Claim 6
Dependent Claim
17 words
A convertible snow plow according to claim 1 in which said ground-contacting supporting elements are caster wheels.
Claim 7
Dependent Claim
77 words
A convertible snow plow according to claim 1 in which said hydraulic control circuit means includes a tank connected to the outlet of said relief valve means and between said pump and said jacks, a three-way valve connected respectively to said pump and tank and relief valve, said three-way valve being movable to an ON position effective to direct pressure fluid from said pump to said jacks and thereby exert a lifting force on said moldboard assembly.
Claim 8
Dependent Claim
124 words
A convertible snow plow according to claim 6 having additional hydraulic jacks connected between said moldboard and said second blade, and said hydraulic control circuit means includes a four-way valve connected respectively to opposite ends of said additional hydraulic jacks and tank and pump, said four-way valve being movable to two ON positions for directing fluid under pressure selectively to opposite ends of said additional jacks for moving said second blade to said extended and retracted positions while returning fluid from the opposite ends to tank, and said four-way valve being movable to an OFF position blocking return of fluid from either end of said additional hydraulic jacks to tank to thereby hold said second blade selectively in its said extended and retracted positions.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-02-25 | 1977-08-27 | 1978-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-25 | 1981-08-27 | 1982-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-25 | 1985-08-27 | 1986-02-26 | $7700.00 | Window Closed / Lapsed |