US3929267A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sheet material transport
Assignee: Individual
•
Filing: 1973-09-21
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Granted: 1975-12-30
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Expires: 1993-09-21
Abstract
Abstract A tractor for feeding a paper web is disclosed in which the drive means forms an integral part of the tractor. A tractor belt is guided around a closed loop path and carries pins for engaging perforations in the web and magnetic elements which are acted on by a pattern of magnetic fields generated by a row of coils arranged alongside a portion of the path. The coils are energised in a manner to cause the pattern of fields to move in steps and thereby cause the magnetic elements, and hence the belt and pins, to move in steps.
Inventors
- 👤 Alan Foster
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 23:35
CPC Classifications
B; B41; B41J; B41J11/00; B41J11/26; B41J11/30
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
113 words
Web feeding apparatus including guide means to guide an endless belt around a path having a linear portion; means on the belt arranged to engage the web at least during travel along the linear portion of the path; a plurality of spaced magnetic elements carried on the belt; and means operable to generate a pattern of magnetic fields which moves along at least a portion of the path in a sequence of steps, the magnetic fields being effective to co-operate with the magnetic elements on the belt to cause the magnetic elements and the belt to move along the path in steps corresponding to the stepping movement of the pattern of magnetic fields.
Claim 2
Dependent Claim
113 words
Web feeding apparatus including guide means to guide an endless belt around a path having a linear portion; means on the belt arranged to engage the web at least during travel along the linear portion of the path; a plurality of spaced magnetic elements carried on the belt; and means operable to generate a pattern of magnetic fields which moves along at least a portion of the path in a sequence of steps, the magnetic fields being effective to co-operate with the magnetic elements on the belt to cause the magnetic elements and the belt to move along the path in steps corresponding to the stepping movement of the pattern of magnetic fields.
Claim 3
Dependent Claim
109 words
Apparatus as claimed in claim 1 including a row of coils located along the portion of the path and electrically connected in three interlaced groups such that each coil of a group lies between two coils from the other two groups; the coils of two of the groups being energised with one polarity of current and the coils of the other group being energised with the opposite polarity of current to generate the pattern of magnetic fields, movement of the pattern by a step being affected by reversing the polarity of energisation of the coils of said other group and of the coils of one of said two groups.
Claim 4
Dependent Claim
77 words
Apparatus as claimed in claim 2 including a pair of elongate magnetic cores extending in spaced parallel relationship adjacent and parallel to the portion of the path, in which each core carries a row of coils electromagnetically coupled thereto, the magnetic elements moving between the magnetic cores in their movement along the portion of the path; and energisation of the coils being effective to generate the pattern of magnetic fields in the space between the magnetic cores.
Claim 5
Dependent Claim
77 words
Apparatus as claimed in claim 1 in which the path consists of first and second linear portiOns spaced apart and parallel to one another connected by substantially semicircular sections defined by semicircular guide surfaces and inclusing first and second means operable to generate patterns of magnetic fields along the first and second linear portions respectively, the first and second means being operated in synchronism to drive the belt in steps along the first and second linear portions.
Claim 6
Dependent Claim
37 words
Apparatus as claimed in claim 4 in which the magnetic elements project inwardly from the belt and each semicircular guide surfaces are provided by two guides spaced apart to permit the passage of the magnetic elements therebetween.
Claim 7
Dependent Claim
26 words
Apparatus as claimed in claim 1 in which the magnetic elements each include a carrier secured to the belt and a magnet secured to the carrier.
Claim 8
Dependent Claim
23 words
Apparatus as claimed in claim 6 in which each magnetic element carries a pin operative to engage in a perforation of the web.
Claim 9
Dependent Claim
25 words
Apparatus as claimed in claim 1 including pins carried by the belt and projecting outwardly from the belt to engage in perforations in the web.
References Cited (Backward Citations)
US2731212A
Cited
US3289904A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-12-29 | 1979-06-30 | 1979-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-29 | 1983-06-30 | 1983-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-29 | 1987-06-30 | 1987-12-30 | $7700.00 | Window Closed / Lapsed |