Patent US1939876A successfully refreshed from Google Patents.
Patent US4873767A successfully refreshed from Google Patents.
US4873767A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Safety letter opener
Assignee: Individual
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Filing: 1988-06-20
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Granted: 1989-10-17
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Expires: 2008-06-20
Abstract
Abstract An implement is provided for opening envelopes in which a ram is reciprocally mounted within a hollow sleeve. A transverse envelope receiving crevice or slot is defined at one end of the sleeve and the ram carries a blade which has a cutting edge directed toward the envelope receiving slot. A spring acts between the sleeve and the ram to urge the cutting edge of the blade away from the transverse slot so that the blade is not exposed unless the spring bias is overcome.
Inventors
- 👤 Hin C. Lok
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 16:06
CPC Classifications
B; B26; B26B; B26B27/00; B43; B43K; B43K29/00; B43K29/18; B43M; B43M7/00; B43M7/002
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
226 words
A device for opening an envelope comprising a hollow sleeve formed by longitudinal surrounding walls extending parallel to a linear longitudinal direction of movement and which define a cavity therewith having an open end and at its opposite end a solid end wall extending perpendicular to said longitudinal direction of movement and joined to and spaced longitudinally from said longitudinal surrounding walls to define an envelope receiving slot of uniform width throughout extending perpendicular to said direction of movement, a ram extending into said open end of said sleeve whereby said sleeve and said ram are movable relative to each other in telescoping, linear reciprocal fashion in said longitudinal direction of movement, a blade mounted on said ram having at least one cutting edge directed toward said slot and disposed within said cavity and extending in said longitudinal direction of movement, means operable externally of said sleeve and said ram for adjustably limiting the extent of relative longitudinal movement between said ram and said sleeve to control the maximum extent to which said blade is movable longitudinally into said slot and to prevent said cutting edge of said blade from extending across the entire width of said slot, and biasing means captured within said cavity and between said sleeve and said ram and disposed to urge said cutting edge of said blade away from said slot.
Claim 2
Independent Claim
226 words
A device for opening an envelope comprising a hollow sleeve formed by longitudinal surrounding walls extending parallel to a linear longitudinal direction of movement and which define a cavity therewith having an open end and at its opposite end a solid end wall extending perpendicular to said longitudinal direction of movement and joined to and spaced longitudinally from said longitudinal surrounding walls to define an envelope receiving slot of uniform width throughout extending perpendicular to said direction of movement, a ram extending into said open end of said sleeve whereby said sleeve and said ram are movable relative to each other in telescoping, linear reciprocal fashion in said longitudinal direction of movement, a blade mounted on said ram having at least one cutting edge directed toward said slot and disposed within said cavity and extending in said longitudinal direction of movement, means operable externally of said sleeve and said ram for adjustably limiting the extent of relative longitudinal movement between said ram and said sleeve to control the maximum extent to which said blade is movable longitudinally into said slot and to prevent said cutting edge of said blade from extending across the entire width of said slot, and biasing means captured within said cavity and between said sleeve and said ram and disposed to urge said cutting edge of said blade away from said slot.
Claim 3
Dependent Claim
22 words
A device according to claim 1 wherein said biasing means is a compressed coil spring disposed between said sleeve and said ram.
Claim 4
Dependent Claim
64 words
A device according to claim 2 wherein together said ram and said sleeve define an enclosed spring compartment having opposite, transverse end walls, one of which is formed by the structure of said sleeve and the other of which is formed by the structure of said ram and said spring is longitudinally oriented within said compartment and is compressed between said opposite end walls.
Claim 5
Dependent Claim
26 words
A device according to claim 3 further comprising a spring guide interposed between said spring and said end wall formed by said structure of said ram.
Claim 6
Dependent Claim
69 words
A device according to claim 4 wherein said blade is formed with a surface discontinuity and wherein said ram is formed with a blade engaging stud which projects laterally into said spring compartment, and said blade is mounted in said spring compartment such that said blade engaging stud engages said surface discontinuity of said blade and said spring guide constrains said blade against lateral movement within said spring compartment.
Claim 7
Dependent Claim
53 words
A device according to claim 1 wherein said sleeve is formed with a longitudinally oriented track closed at both ends and located adjacent to said ram and said ram is formed with a depressible tang which projects into said track to thereby hold said ram and said sleeve together in a releasable manner.
Claim 8
Dependent Claim
60 words
A device according to claim 1 wherein said means for adjustably limiting relative movement between said ram and said sleeve is comprised of a disk mounted for rotation on one of said ram and said sleeve about an eccentric axis perpendicular thereto and the other of said ram and said sleeve is relatively movable in longitudinal reciprocation into abutment therewith.
Claim 9
Dependent Claim
126 words
An implement for opening envelopes comprising a hollow sleeve defining a cavity therewithin and forming a transverse channel at one extremity thereof, a ram element disposed within said cavity, guide means acting between said sleeve and said ram to limit relative movement therebetween to longitudinal reciprocation, a blade disposed within said cavity and having a cutting edge directed toward said transverse channel, adjustable blade movement control means which limits the extent to which said cutting edge of said blade projects into said channel to a predetermined distance which is less than the width of said channel, and spring biasing means which acts to bias said ram relative to said channel such that said cutting edge of said blade is retracted within said cavity of said sleeve.
Claim 10
Dependent Claim
126 words
An implement for opening envelopes comprising a hollow sleeve defining a cavity therewithin and forming a transverse channel at one extremity thereof, a ram element disposed within said cavity, guide means acting between said sleeve and said ram to limit relative movement therebetween to longitudinal reciprocation, a blade disposed within said cavity and having a cutting edge directed toward said transverse channel, adjustable blade movement control means which limits the extent to which said cutting edge of said blade projects into said channel to a predetermined distance which is less than the width of said channel, and spring biasing means which acts to bias said ram relative to said channel such that said cutting edge of said blade is retracted within said cavity of said sleeve.
Claim 11
Dependent Claim
67 words
An implement according to claim 8 wherein said sleeve defines a transverse partition, one side of which defines a wall of said channel and the other side of which defines a transverse bearing wall, and said ram also defines a transverse tearing wall longitudinally displaced from that of said sleeve, and said spring biasing means is comprised of a coil spring compressed between said transverse bearing walls.
Claim 12
Dependent Claim
22 words
An implement according to claim 9 further comprising means for maintaining said coil spring in longitudinal alignment between said transverse bearing walls.
Claim 13
Dependent Claim
49 words
An implement according to claim 8 in which said ram defines a laterally projecting stud and said blade is formed with an aperture therethrough, and said blade is immobilized from longitudinal movement relative to said ram by engagement cf said laterally projecting stud in said aperture of said blade.
Claim 14
Dependent Claim
58 words
An implement according to claim 8 wherein one of said sleeve and said ram is formed with a laterally projecting depressible member and the other of said sleeve and said ram is formed with a longitudinally aligned track closed at both ends, whereby said depressible member extends into said track to releasably hold said sleeve on said ram.
Claim 15
Dependent Claim
122 words
An implement for opening envelopes comprising a hollow sleeve defining a cavity therewithin and open at one end and closed at an opposite end by a transverse means which defines a transverse envelope receiving crevice, ram mounted for longitudinal reciprocation within said cavity of said sleeve and extending into said open end thereof, a blade disposed within said cavity and having a cutting edge directed toward said envelope receiving crevice, an adjustable blade movement control means which limits the extent to which said blade projects into said crevice to less than the width thereof, and spring biasing means acting between said sleeve and said ram to urge said cutting edge of said blade away from said transverse crevice and into said cavity.
Claim 16
Dependent Claim
122 words
An implement for opening envelopes comprising a hollow sleeve defining a cavity therewithin and open at one end and closed at an opposite end by a transverse means which defines a transverse envelope receiving crevice, ram mounted for longitudinal reciprocation within said cavity of said sleeve and extending into said open end thereof, a blade disposed within said cavity and having a cutting edge directed toward said envelope receiving crevice, an adjustable blade movement control means which limits the extent to which said blade projects into said crevice to less than the width thereof, and spring biasing means acting between said sleeve and said ram to urge said cutting edge of said blade away from said transverse crevice and into said cavity.
Claim 17
Dependent Claim
39 words
An implement according to claim 13 wherein said spring biasing means is comprised of a longitudinally aligned compressed coil spring interposed between said sleeve and said ram to urge said ram away from said opposite end of said sleeve.
Claim 18
Dependent Claim
22 words
An implement according to claim 14 further comprising releasable means for preventing said ram and said sleeve from separating from each other.
Claim 19
Dependent Claim
19 words
An implement according to claim 13 wherein said width of said channel is no greater than about 0.5 centimeters.
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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) | 1992-10-16 | 1993-04-17 | 1993-10-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-16 | 1997-04-17 | 1997-10-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-16 | 2001-04-17 | 2001-10-17 | $7700.00 | Window Closed / Lapsed |