US3668814A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Surface grinding device
Assignee: 3M Co
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Filing: 1970-03-30
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Granted: 1972-06-13
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Expires: 1990-03-30
Abstract
Abstract A method of and an apparatus for grinding a planar surface on a workpiece when the workpiece is pressed against an abrasive belt moving in an arcuate path. The workpiece is held by the apparatus with the plane at which the planar surface is to be formed oriented generally parallel to the axis of the arcuate path of the abrasive belt, and is moved about an axis normal to and intersecting the axis of the arcuate path while it is pressed into high pressure grinding contact with the abrasive belt to move the workpiece toward the abrasive belt in a direction normal to the axis of the path of the abrasive belt. When the plane at which the planar surface to be formed is tangent to the abrasive belt, the movement of the workpiece toward the belt is halted so that the desired planar surface is formed on the workpiece.
Inventors
- 👤 Conrad T Freerks
- 👤 Fred R Luecke Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:22
CPC Classifications
B; B24; B24B; B24B21/00
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
206 words
A method of forming a planar surface on a metal workpiece through use of an abrasive belt having a given width between its spaced edges which comprises the steps of: driving the abrasive belt along an arcuate path having an axis; holding the workpiece with the plane at which the planar surface is to be formed oriented essentially parallel to the axis of the arcuate path about which the abrasive belt is driven; moving the workpiece about an axis positioned between the edges of the abrasive belt, which axis of movement is normal to the axis of the arcuate path; urging the workpiece toward the arcuate path of said abrasive belt in a direction parallel to the axis of movement, said moving and urging of the workpiece affording grinding contact between the workpiece and the abrasive belt at a pressure in the contact area of not less than 300 pounds per square inch to advance the workpiece toward the abrasive belt; and stopping the advancing movement of the workpiece toward the abrasive belt when the desired plane is tangent to the abrasive belt on the arcuate path so that the planar surface will be formed upon further rotation of the workpiece, thereby relieving the grinding pressure.
Claim 2
Independent Claim
206 words
A method of forming a planar surface on a metal workpiece through use of an abrasive belt having a given width between its spaced edges which comprises the steps of: driving the abrasive belt along an arcuate path having an axis; holding the workpiece with the plane at which the planar surface is to be formed oriented essentially parallel to the axis of the arcuate path about which the abrasive belt is driven; moving the workpiece about an axis positioned between the edges of the abrasive belt, which axis of movement is normal to the axis of the arcuate path; urging the workpiece toward the arcuate path of said abrasive belt in a direction parallel to the axis of movement, said moving and urging of the workpiece affording grinding contact between the workpiece and the abrasive belt at a pressure in the contact area of not less than 300 pounds per square inch to advance the workpiece toward the abrasive belt; and stopping the advancing movement of the workpiece toward the abrasive belt when the desired plane is tangent to the abrasive belt on the arcuate path so that the planar surface will be formed upon further rotation of the workpiece, thereby relieving the grinding pressure.
Claim 3
Dependent Claim
40 words
A method according to claim 1, further comprising the step of: varying the path of contact between the abrasive belt and the surface of a workpiece along the axis of the arcuate path about which the abrasive belt is driven.
Claim 4
Dependent Claim
32 words
A method according to claim 1, further comprising the step of: reciprocating the abrasive belt back and forth along the axis of the arcuate path about which the abrasive belt is driven.
Claim 5
Dependent Claim
62 words
A method according to claim 1, wherein said moving step comprises moving the workpiece about said axis at a first rate during the initial grinding of a workpiece on the abrasive belt, and moving the workpiece about the axis at a second rate of angular velocity which is substantially higher than the first rate before separation of the workpiece from the belt.
Claim 6
Dependent Claim
33 words
A method according to claim 1, wherein said moving step comprises rotating said workpiece about an axis passing through the center of said workpiece to form concentric grinding marks on said planar surface.
Claim 7
Independent Claim
179 words
An apparatus for forming a planar surface on a workpiece which comprises: an abrasive belt; means for driving said abrasive belt in an arcuate path; means for holding a said workpiece with the plane on the workpiece at which said planar surface is to be formed oriented generally parallel to the axis of said arcuate path about which said abrasive belt is driven; means for rotating said holding means at a predetermined speed about an axis normal to the axis of said arcuate path, for advancing said holding means and a said workpiece from a first position at which a said workpiece is spaced from said abrasive belt toward a second position where said planar surface is tangent with said abrasive belt on said arcuate path, and for exerting a grinding pressure of at least 300 pounds per square inch between a said workpiece and said abrasive belt in the area of grinding contact so that material will be efficiently removed from a said workpiece until said planar surface is substantially formed on said workpiece at said second position.
Claim 8
Independent Claim
179 words
An apparatus for forming a planar surface on a workpiece which comprises: an abrasive belt; means for driving said abrasive belt in an arcuate path; means for holding a said workpiece with the plane on the workpiece at which said planar surface is to be formed oriented generally parallel to the axis of said arcuate path about which said abrasive belt is driven; means for rotating said holding means at a predetermined speed about an axis normal to the axis of said arcuate path, for advancing said holding means and a said workpiece from a first position at which a said workpiece is spaced from said abrasive belt toward a second position where said planar surface is tangent with said abrasive belt on said arcuate path, and for exerting a grinding pressure of at least 300 pounds per square inch between a said workpiece and said abrasive belt in the area of grinding contact so that material will be efficiently removed from a said workpiece until said planar surface is substantially formed on said workpiece at said second position.
Claim 9
Dependent Claim
46 words
An apparatus according to claim 6, which further comprises: means for providing relative movement between said abrasive belt and said workpiece along the axis of the arcuate path, thereby varying the path of contact of a said workpiece on said abrasive belt throughout the grinding process.
Claim 10
Dependent Claim
43 words
An apparatus according to claim 6, which further comprises: means for reciprocating said abrasive belt back and forth along the axis of said arcuate path, thereby varying the path of contact of a said workpiece on said abrasive belt throughout the grinding process.
Claim 11
Dependent Claim
60 words
An apparatus according to claim 7, wherein said last mentioned means comprises air cylinder means for urging said holding means toward said second position, and means are provided for increasing the rate of rotation of said rotating means for said holding means after said holding means reaches said second position to increase the rate of completion of said planar surface.
Claim 12
Dependent Claim
30 words
An apparatus according to claim 9, further comprising: adjustable stop means for determining said second position of said holding means with respect to said abrasive belt on said arcuate path.
Claim 13
Dependent Claim
84 words
An apparatus according to claim 7, wherein said means for driving said abrasive belt in an arcuate path comprises a roller and means for moving said axis of said rotating means to move said plane on a said workpiece at which a said planar surface is to be formed to a predetermined position slightly out of parallel with the axis of said arcuate path to equalize the rate of material removal across the surface of a said workpiece after said second position is reached.
Claim 14
Dependent Claim
23 words
An apparatus according to claim 6 wherein the axis about which the holding means is rotated intersects the axis of said arcuate path.
Claim 15
Dependent Claim
102 words
A method according to claim 1, wherein said moving and urging of the workpiece affords grinding contact between the workpiece and the abrasive belt at a minimum pressure in the contact zone of between 300 and 600 pounds per square inch which pressure is further selected for the specific material in accordance with the following table: Abrasive Minimum grinding pressure Metal Belt (in pounds per sq. inch) Grade Ductile, malleable, 24X 400 and grey iron 36X 350 Carbon steel, 35 Rc hardness 24X 375 Carbon steel 60+ Rc hardness 36X 300 304 Stainless steel 36X 600 High Nickel Alloy metals 50X 500
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) | 1975-06-13 | 1975-12-13 | 1976-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-13 | 1979-12-13 | 1980-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-13 | 1983-12-13 | 1984-06-13 | $7700.00 | Window Closed / Lapsed |