US4854786A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Computer controlled automatic shift drill
Assignee: Allen Bradley Co LLC
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Filing: 1988-05-26
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Granted: 1989-08-08
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Expires: 2008-05-26
Abstract
Abstract The trust exerted on a drill bit is sensed and employed to determine the speed at which the bit is driven. A controller for the drill compares the thrust to a predetermined threshold value and in response to the comparison emits a control signal which shifts a transmission in the drill into high or low speed. After each shift, a number of thrust samples are taken in order to compute an average thrust for different strata of the material being drilled. At the completion of drilling each hole, the average thrusts for the hole are used to recalibrate the shift threshold value. In this manner, the shift threshold is adjusted to compensate for drill bit wear. The sensed thrust is also compared to a bit reject threshold value to determine when the bit is too dull for proper drilling.
Inventors
- 👤 Robert H. Alexander
- 👤 Thomas M. Osmer
- 👤 James W. Neely
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 07:31
CPC Classifications
G; G05; G05B; G05B19/00; G05B19/02; G05B19/18; G05B19/416; G05B19/4163; G05B2219/00; G05B2219/30; G05B2219/37; G05B2219/37344; G05B2219/45; G05B2219/45129; Y; Y10; Y10T; Y10T408/00; Y10T408/03; Y10T408/13; Y10T408/14; Y10T408/16; Y10T408/165; Y10T408/17; Y10T408/172; Y10T409/00; Y10T409/30; Y10T409/306664; Y10T409/306776; Y10T409/306832; Y10T409/306888; Y10T409/307224; Y10T409/30728
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
77 words
A mechanism for forming a workpiece with a tool comprising: a means for rotationally driving the tool at one of two speeds; a means for sensing a force applied to the tool; a first means for comparing the sensed force to a first threshold value; means for shifting the speed of said means for driving in response to the first means for comparing; and means, responsive to the sensed force, for periodically redefining the first threshold value.
Claim 2
Dependent Claim
77 words
A mechanism for forming a workpiece with a tool comprising: a means for rotationally driving the tool at one of two speeds; a means for sensing a force applied to the tool; a first means for comparing the sensed force to a first threshold value; means for shifting the speed of said means for driving in response to the first means for comparing; and means, responsive to the sensed force, for periodically redefining the first threshold value.
Claim 3
Dependent Claim
30 words
The mechanism as recited in claim 1 further comprising a second means for comparing the sensed force to a second threshold value to determine when the tool engages the workpiece.
Claim 4
Dependent Claim
31 words
The mechanism as recited in claim 2 further comprising a third means for comparing the sensed force to a third threshold to determine when the tool has penetrated through the workpiece.
Claim 5
Dependent Claim
25 words
The mechanism as recited in claim 3 wherein said means for shifting the speed is further responsive to the second and third means for comparing.
Claim 6
Dependent Claim
25 words
The mechanism as recited in claim 1 further comprising: fourth means for comparing the sensed force to a fourth threshold value to determine tool wear.
Claim 7
Dependent Claim
25 words
The mechanism as recited in claim 1 further comprising means for retracting the tool from the workpiece in response to the fourth means for comparing.
Claim 8
Independent Claim
112 words
A method for controlling the speed of a tool driven by a machine having a first speed that is faster than a second speed, said method comprising: sensing a force exerted on the tool; comparing the sensed force to a first threshold value; shifting the speed of the machine to the second speed in response to the sensed force exceeding the first threshold value, and to the first speed in response to the sensed force being below the first threshold value; determining the average force exerted on the tool during a given period of time after a shift in speed; and employing the determined average force to redefine the first threshold value.
Claim 9
Independent Claim
112 words
A method for controlling the speed of a tool driven by a machine having a first speed that is faster than a second speed, said method comprising: sensing a force exerted on the tool; comparing the sensed force to a first threshold value; shifting the speed of the machine to the second speed in response to the sensed force exceeding the first threshold value, and to the first speed in response to the sensed force being below the first threshold value; determining the average force exerted on the tool during a given period of time after a shift in speed; and employing the determined average force to redefine the first threshold value.
Claim 10
Dependent Claim
21 words
The method as recited in claim 7 wherein the given period begins a first interval of time after a shift occurs.
Claim 11
Dependent Claim
56 words
The method as recited in claim 7 further comprising: initially comparing the sensed force to a second threshold value to determine when the tool contacts a workpiece; shifting the machine to the second speed upon a determination that the tool has contacted the workpiece; and inhibiting a subsequent shift in speed for a given interval thereafter.
Claim 12
Dependent Claim
39 words
The method as recited in claim 7 wherein said shifting the speed of the machine to the first speed occurs only if the force remains below the first threshold value at the end of a second interval of time.
Claim 13
Dependent Claim
50 words
The method as recited in claim 7 further comprising: comparing the sensed force to a third threshold value to determine when the tool has penetrated through a workpiece; and shifting the speed of the machine to the second speed upon a determination that the tool has penetrated through the workpiece.
Claim 14
Dependent Claim
75 words
The method as recited in claim 7 wherein an average force is determined after each of a plurality of shifts in speed, and wherein said step of employing the average force to redefine the first threshold value comprises: selecting one of the average forces which has a predetermined relationship to the average force of the greatest magnitude; and setting the first threshold value to the sum of the selected average force and an offset value.
Claim 15
Dependent Claim
202 words
A drill for rotationally driving a bit into a workpiece to form a hole comprising: a prime mover; a transmission, coupled to said prime mover, for selectively driving the bit at either a first or a second speed; means for sensing a force applied to the bit; means for comparing the sensed force to a plurality of threshold values; means, responsive to the means for comparing, for shifting the speed of the transmission (1) to the first speed for a first interval upon the sensed force exceeding a first threshold value, (2) thereafter shifting the speed of the transmission to the first speed in response to the sensed force being above a second threshold value and to the second speed in response to the sensed force being below the second threshold value, and (3) shifting the speed of the transmission to the first speed whenever the sensed force is below a third threshold value; means for determining the value of the average force exerted on the bit during a second interval of time after each shift in speed in response to the force crossing the second threshold value; and means, responsive to the average force values, for redefining the second threshold value.
Claim 16
Dependent Claim
202 words
A drill for rotationally driving a bit into a workpiece to form a hole comprising: a prime mover; a transmission, coupled to said prime mover, for selectively driving the bit at either a first or a second speed; means for sensing a force applied to the bit; means for comparing the sensed force to a plurality of threshold values; means, responsive to the means for comparing, for shifting the speed of the transmission (1) to the first speed for a first interval upon the sensed force exceeding a first threshold value, (2) thereafter shifting the speed of the transmission to the first speed in response to the sensed force being above a second threshold value and to the second speed in response to the sensed force being below the second threshold value, and (3) shifting the speed of the transmission to the first speed whenever the sensed force is below a third threshold value; means for determining the value of the average force exerted on the bit during a second interval of time after each shift in speed in response to the force crossing the second threshold value; and means, responsive to the average force values, for redefining the second threshold value.
Claim 17
Dependent Claim
59 words
The drill as recited in claim 13 wherein the means for redefining the second threshold value includes means: for selecting the average force value which has a predetermined relationship to the average force value of the greatest magnitude; and means for setting the second threshold value to the sum of the selected average force value and a offset value.
Claim 18
Dependent Claim
17 words
The drill as recited in claim 13 further comprising means for storing samples of the sensed force.
Claim 19
Dependent Claim
44 words
The drill as recited in claim 13 wherein the means for shifting the speed of the transmission further includes means for delaying the shifting to the second speed for a third interval of time after the sensed force drops below the second threshold value.
Claim 20
Dependent Claim
38 words
The drill as recited in claim 13 wherein the means for determining the values of the average force commences the second interval of time upon the expiration of a fourth interval of time after a shift in speed.
Claim 21
Dependent Claim
28 words
The drill as recited in claim 13 further comprising means for disabling advancement of the drill into the workpiece upon the sensed force exceeding a fourth threshold value.
Claim 22
Dependent Claim
103 words
A drill having a bit for forming a hole in a workpiece comprising: a means for selectively rotationally driving the bit at either a first or a second speed; means for sensing a force applied to the bit; means for comparing the sensed force to a threshold value; means, responsive to the means for comparing, for shifting the speed of said means for driving (1) to the first speed in response to the sensed force being above the threshold value, and (2) to the second speed in response to the force being below the threshold value for a first predetermined period of time.
Claim 23
Dependent Claim
103 words
A drill having a bit for forming a hole in a workpiece comprising: a means for selectively rotationally driving the bit at either a first or a second speed; means for sensing a force applied to the bit; means for comparing the sensed force to a threshold value; means, responsive to the means for comparing, for shifting the speed of said means for driving (1) to the first speed in response to the sensed force being above the threshold value, and (2) to the second speed in response to the force being below the threshold value for a first predetermined period of time.
Claim 24
Dependent Claim
47 words
The drill as recited in claim 19 further comprising: means for determining the value of the average force exerted on the bit during a second predetermined period of time after a shift in speed; and means, responsive to the average force values, for redefining the threshold value.
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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) | 1992-08-07 | 1993-02-06 | 1993-08-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-07 | 1997-02-06 | 1997-08-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-07 | 2001-02-06 | 2001-08-08 | $7700.00 | Window Closed / Lapsed |