US3431617A - Cylindrical drum - Google Patents

Cylindrical drum Download PDF

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Publication number
US3431617A
US3431617A US560726A US3431617DA US3431617A US 3431617 A US3431617 A US 3431617A US 560726 A US560726 A US 560726A US 3431617D A US3431617D A US 3431617DA US 3431617 A US3431617 A US 3431617A
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US
United States
Prior art keywords
drum
cylinder
base plate
cylindrical
auxiliary
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US560726A
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English (en)
Inventor
Jan Van Der Hilst
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Philips North America LLC
US Philips Corp
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US Philips Corp
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Filing date
Publication date
Application filed by US Philips Corp filed Critical US Philips Corp
Application granted granted Critical
Publication of US3431617A publication Critical patent/US3431617A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C13/00—Rolls, drums, discs, or the like; Bearings or mountings therefor
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B17/00—Guiding record carriers not specifically of filamentary or web form, or of supports therefor
    • G11B17/32—Maintaining desired spacing between record carrier and head, e.g. by fluid-dynamic spacing
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B25/00—Apparatus characterised by the shape of record carrier employed but not specific to the method of recording or reproducing, e.g. dictating apparatus; Combinations of such apparatus
    • G11B25/02—Apparatus characterised by the shape of record carrier employed but not specific to the method of recording or reproducing, e.g. dictating apparatus; Combinations of such apparatus using cylindrical record carriers

Definitions

  • This invention relates to cylindrical drums of the type which is provided with a base plate at or near at least one extremity and which is rotatable about its own axis. In such a cylindrical drum it is known to secure the base plate directly and rigidly to the drum.
  • the rigid connection due to the radial expansion of the base plate being considerably less than that of the wall of the drum, will influence the action of the centrifugal forces on the wall of the drum so that the drum assumes the bulging shape of a barrel which differs from the cylindrical shape. If such a cylindrical drum is used as a quick-rotating memory drum for magnetic recordings, the barrel-shaped deformation of the periphery of the cylinder will result in intolerable variations in the width of the gap between the surface of the drum and the memory head.
  • An object of the invention is to provide a fastening construction between the drum and the base plate, which is such that the wall of the drum can expand freely in the radial direction throughout its length and hence the cylindrical shape is retained at any arbitrary, even very high rotational speed of the "drum.
  • a cylindrical drum of the kind mentioned above is characterised in that the drum is secured to the base plate by means of a hollow auxiliary cylinder the extremities of which are connected to the wall of the drum and the base plate, respectively, the length L, the mean radius R and the wall thickness t of the auxiliary cylinder being chosen to s be such that whilst the material and the dimensions of the auxiliary cylinder are such that for the drum and the cylinder the expression pR /E is the same or approximately the same, where:
  • R mean radius (half the sum of the external and internal radii),
  • the length L of the auxiliary cylinder is equal to L 2.5 /Rt the cylinder may be regarded with respect to radialsymmetrical deformation as infinitely long, that is to say the radial expansion occurring at the extremity which is connected to the base plate has no influence on 3,431,617 Patented Mar. 11, 1969 'ice the radial expansion of the other extremity which is connected to the drum.
  • a suitable embodiment of the invention consists in that the auxiliary cylinder lies within the drum and is made of similar material to that of the drum, the auxiliary cylinder having an external diameter and a wall so thin in proportion to the wall thickness of the drum, that the mean radius of the auxiliary cylinder approximates as far as possible that of the drum.
  • the advantage of the embodiment consists in that the total length of the drum construction is minimized, which is important, for example, for memory drums in which a maximum number of recordings per unit structural volume is aimed at.
  • Another suitable embodiment of the invention consists in that an annular groove concentric with the axis of the drum is formed in the wall of the drum at the extremity engaging the base plate and extends inwardly through part of the length of the drum.
  • the last-mentioned embodiment has the further advantage that it is possible to make the mean radii of the drum and of the auxiliary cylinder more nearly equal to each other so that, upon expansion of the wall of the drum during high speed rotation, the cylindrical shape is retained with more accurate approximation.
  • FIG. 1 shows a longitudinal section of one end part of a drum according to the invention
  • FIG. 2 shows a longitudinal section of a modification of one end of the drum.
  • FIG. 1 shows part of a cylindrical drum 1 which is secured, at least at one end, to a base plate 2 through the intermediary of a hollow auxiliary cylinder 3 placed in the drum and having ends 4 and S which are connected, for example by welding, to the drum 1 and the base plate 2 respectively.
  • the drum 1 is supported to rotate about its own axis in a manner not shown.
  • auxiliary cylinder 3 The dimensions of the auxiliary cylinder 3 are chosen to be such that LE2.5 /Rt where L is the length, R is the mean radius (half the sum of the external and internal radii), and t is the wall thickness of the cylinder 3. If this relationship is fulfilled, the auxiliary cylinder may be considered with regard to radial-symmetrical deformation as infinitely long, which means that radial deformation occurring at one end of the cylinder does not result in radial displacements of points at the other end of the cylinder.
  • the auxiliary cylinder 3 is made of a material similar to that of the drum 1.
  • the cylinder 3 is placed at a substantial fit in the drum and has a wall which is thin in proportion to the wall thickness of the drum, in order that the mean radius of the cylinder approximates to that of the drum as far as possible. Consequently the expression pR /E for the drum and the cylinder and hence the radial expansions of the ends 4 of the 3 cylinder and the associated ends of the drum are substantially the same. In fact, the expansion of the end of the drum is not influenced by the attachment at the end 5 since the cylinder 3 may be regarded as infinitely long.
  • an exact fit between the drum and the cylinder exists at least at the base plate 2 in order to permit the drum, supported by the cylinder and the base plate, to be machined, for example turned off, at its outer periphery, the base plate being able to absorb via the cylinder the radial forces which occur during this process.
  • This fit intended for machining will undo during the quick rotation of the drum.
  • annular groove 7 is formed at that end of the drum 9 provided with the base plate which is formed by a wall part of the drum.
  • the groove 7 divides the wall of the drum into an outer cylinder and an inner cylinder 6', the inner cylinder 6' constituting the auxiliary cylinder.
  • the groove 7 has a width and a depth such that the auxiliary cylinder 6' may again be regarded as infinitely long.
  • the mean radii of the drum 9 and the cylinder 6' may more nearly approximate to each other than in the embodiment of FIG. 1, so that the cylindrical shape of the drum during rotation of the drum may be retained with even more accurate approximation.
  • the base plate 10 to which the free end 11 of the cylinder 6 is secured, for example by gluing, is placed as a close fit in the end of the drum in order to permit the drum supported by the base plate, to be machined at its outer periphery.
  • the invention is not limited to quick-rotating memory drums but also applicable to fastrotating cylindrical drums in general which have to satisfy the condition of maintaining their cylindrical shape during high-speed rotation.
  • a rotatable drum comprising a cylindrical body portion rotatable about the central axis thereof, a base plate member arranged at one end of said cylindrical body portion and having a central axis coincident with the axis of said cylindrical body portion, and means interconnecting said base plate and the cylindrical body portion, said means comprising an auxiliary cylindrical member having one end secured to the cylindrical body portion at an end portion thereof and having the other end thereof secured to said base plate at a peripheral portion thereof, said auxiliary cylindrical member having an effective length L 2.5 /R t and a characteristic p R /E approximating the characteristic p R /E of the cylindrical body portion wherein R and R represent respectively the mean radius of the auxiliary cylindrical member and of the cylindrical body portion, t is the wall thickness of the auxiliary cylindrical member, p and p represent respectively the specific mass of the auxiliary cylindrical body and of the cylindrical body portion, and E and E represent respectively the elasticity modulus of the auxiliary cylindrical body and of the cylindrical body portion.
  • a rotatable drum as claimed in claim 1 wherein said cylindrical body portion is provided with an annular groove at the extremity thereof, wherein said cylindrical member is an integral sleeve formed by said groove, and wherein said base plate is secured to the free end of said sleeve.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Photoreceptors In Electrophotography (AREA)
  • Discharging, Photosensitive Material Shape In Electrophotography (AREA)
  • Manufacture Or Reproduction Of Printing Formes (AREA)
  • Rigid Containers With Two Or More Constituent Elements (AREA)
  • Storage Of Web-Like Or Filamentary Materials (AREA)
US560726A 1965-07-22 1966-06-27 Cylindrical drum Expired - Lifetime US3431617A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL6509476A NL6509476A (pt) 1965-07-22 1965-07-22

Publications (1)

Publication Number Publication Date
US3431617A true US3431617A (en) 1969-03-11

Family

ID=19793707

Family Applications (1)

Application Number Title Priority Date Filing Date
US560726A Expired - Lifetime US3431617A (en) 1965-07-22 1966-06-27 Cylindrical drum

Country Status (6)

Country Link
US (1) US3431617A (pt)
CH (1) CH454955A (pt)
DE (1) DE1525196A1 (pt)
FR (1) FR1487612A (pt)
GB (1) GB1087677A (pt)
NL (1) NL6509476A (pt)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3810438A1 (de) * 1988-03-26 1989-10-12 Wilhelm Koenig Zylinderspeicher fuer magnetisch-optische oder optische datenspeicherung und -wiedergabe

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3097590A (en) * 1961-04-12 1963-07-16 Beloit Iron Works Anti-deflection roll
US3138089A (en) * 1963-01-09 1964-06-23 Beloit Corp Anti-deflection roll
US3138848A (en) * 1961-04-21 1964-06-30 Ex Cell O Corp Hollow drum apparatus

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3097590A (en) * 1961-04-12 1963-07-16 Beloit Iron Works Anti-deflection roll
US3138848A (en) * 1961-04-21 1964-06-30 Ex Cell O Corp Hollow drum apparatus
US3138089A (en) * 1963-01-09 1964-06-23 Beloit Corp Anti-deflection roll

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3810438A1 (de) * 1988-03-26 1989-10-12 Wilhelm Koenig Zylinderspeicher fuer magnetisch-optische oder optische datenspeicherung und -wiedergabe

Also Published As

Publication number Publication date
DE1525196A1 (de) 1969-11-27
NL6509476A (pt) 1967-01-23
CH454955A (de) 1968-04-30
GB1087677A (en) 1967-10-18
FR1487612A (fr) 1967-07-07

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