US3578091A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Power-operated impact wrench or screwdriver
Assignee: Air Compressors and Tools Ltd
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Filing: 1969-09-29
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Granted: 1971-05-11
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Expires: 1989-09-29
Abstract
Abstract A power-operated impact wrench, screwdriver or like rotary tool with relatively movable hammer and anvil members and means for automatically causing them to become engaged and disengaged cyclically in which there is means for causing disengagement of the hammer members from the anvil members at a value of torque above a predetermined value comprising an inertia means which is coupled to the hammer member by resilient means the values of which are so chosen that values of torque below the predetermined cutoff value the inertia means is constrained by the resilient means from moving relative to the hammer means and the tool operates in a normal manner while at a value of torque above the predetermined value inertia means move against the action of the resilient means thereby to allow the amount of disengagement movement of members to increase and operate control means to interrupt a supply of power to the tool.
Inventors
- 👤 Ronald Frederick States
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 12:33
CPC Classifications
B; B25; B25B; B25B23/00; B25B23/14; B25B23/145; B25B23/1453
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
165 words
In a power-operated impact wrench, screwdriver or like rotary tool of the kind comprising relatively movable hammer and anvil members with means for automatically causing them to become engaged and disengaged cyclically, and in which there is provided inertia means coupled to the hammer member by resilient means in such manner that, at values of torque below a predetermined value, the inertia means is constrained by the resilient means from mOving relative to the hammer means, while at the predetermined value of torque the inertia means moves relative to the hammer means and thereby acts upon the said automatic means to increase the amount of disengagement movement of the members and operates control means to interrupt a supply of power to the tool, the improvement comprising forming the resilient means as a pair of resilient levers one end of each of which acts upon or is formed integral with a hammer member, and each of which is supported within a bore in the inertia means.
Claim 2
Dependent Claim
165 words
In a power-operated impact wrench, screwdriver or like rotary tool of the kind comprising relatively movable hammer and anvil members with means for automatically causing them to become engaged and disengaged cyclically, and in which there is provided inertia means coupled to the hammer member by resilient means in such manner that, at values of torque below a predetermined value, the inertia means is constrained by the resilient means from mOving relative to the hammer means, while at the predetermined value of torque the inertia means moves relative to the hammer means and thereby acts upon the said automatic means to increase the amount of disengagement movement of the members and operates control means to interrupt a supply of power to the tool, the improvement comprising forming the resilient means as a pair of resilient levers one end of each of which acts upon or is formed integral with a hammer member, and each of which is supported within a bore in the inertia means.
Claim 3
Dependent Claim
64 words
A power-operated impact wrench, screwdriver or like rotary tool as claimed in claim 1, in which the ends of the resilient levers remote from the hammers are acted upon by a cam-operated lever mechanism which prestresses the lever against an abutment surface upon the inertia means positioned in advance of the hammer members when rotated in the normal direction of operation of the tool.
Claim 4
Dependent Claim
55 words
A power-operated impact wrench, screwdriver or like rotary tool as claimed in claim 1 in which each resilient lever presents a different resistance to bending in different radial directions, and is rotatable around its longitudinal axis to change the effective resistance to bending to change the predetermined maximum value of torsion delivered by the tool.
Claim 5
Dependent Claim
60 words
A power-operated impact wrench, screwdriver or like rotary tool as claimed in claim 3, in which each resilient lever is provided with splines at the end opposite to the hammer, which engage corresponding splines in the wall of the bore, and has means for securing the splines in each of its alternative circumferential positions to determine the effective resilience thereof.
Claim 6
Dependent Claim
41 words
A power-operated impact wrench, screwdriver or like rotary tool as claimed in claim 1, in which the inertia member is a hollow cylindrical member which is provided with diametrically opposite longitudinal bores in the wall thereof which house the resilient levers.
Claim 7
Dependent Claim
33 words
A power-operated impact wrench, screwdriver or like rotary tool as claimed in claim 5, in which one end of each resilient lever is circular in cross section and is formed as a hammer.
Claim 8
Dependent Claim
38 words
A power-operated impact wrench, screwdriver or like rotary tool as claimed in claim 4 in which the resilient levers make a close fit in their bores intermediate their ends at the sides of the bore form a fulcrum.
Claim 9
Dependent Claim
94 words
A power-operated impact wrench, screwdriver or like rotary tool all as claimed in claim 7, in which each resilient lever is of different diameter in different radial directions at right angles to one another intermediate their ends, and is provided with two longitudinal flats at right angles to one another at the end opposite the hammer against which rests an adjustable prestressing member, thereby to provide two ranges within which the predetermined pressure can be effected by positioning the resilient lever so as to be engaged at either of the said two longitudinal flats.
Claim 10
Dependent Claim
42 words
A power-operated impact wrench, screwdriver or like rotary tool as claimed in claim 7, in which each resilient lever is tapered and is provided with a longitudinal flat at the end opposite to the hammer against which rests an adjustable prestressing member.
Claim 11
Dependent Claim
59 words
A power-operated impact wrench, screwdriver or like rotary tool as claimed in claim 9, in which the prestressing member is an arcuate lever lying in a plane which is at right angles to the axis of rotation of the inertia member, and situated within a cam ring which is rotatable about an axis to change the value of prestressing.
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) | 1974-05-10 | 1974-11-09 | 1975-05-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-10 | 1978-11-09 | 1979-05-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-10 | 1982-11-09 | 1983-05-11 | $7700.00 | Window Closed / Lapsed |