US3905266A - Bandmill strain system - Google Patents

Bandmill strain system Download PDF

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Publication number
US3905266A
US3905266A US338895A US33889573A US3905266A US 3905266 A US3905266 A US 3905266A US 338895 A US338895 A US 338895A US 33889573 A US33889573 A US 33889573A US 3905266 A US3905266 A US 3905266A
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US
United States
Prior art keywords
journals
pair
bandmill
cross shaft
journal
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
US338895A
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English (en)
Inventor
Jack Weavell
James H Porter
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.)
CAE Machinery Ltd
Original Assignee
CAE Machinery Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by CAE Machinery Ltd filed Critical CAE Machinery Ltd
Priority to US338895A priority Critical patent/US3905266A/en
Priority to CA168,788A priority patent/CA1058485A/fr
Priority to AU66281/74A priority patent/AU473549B2/en
Application granted granted Critical
Publication of US3905266A publication Critical patent/US3905266A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23D—PLANING; SLOTTING; SHEARING; BROACHING; SAWING; FILING; SCRAPING; LIKE OPERATIONS FOR WORKING METAL BY REMOVING MATERIAL, NOT OTHERWISE PROVIDED FOR
    • B23D55/00—Sawing machines or sawing devices working with strap saw blades, characterised only by constructional features of particular parts
    • B23D55/10—Sawing machines or sawing devices working with strap saw blades, characterised only by constructional features of particular parts of devices for tensioning strap saw blades
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T83/00—Cutting
    • Y10T83/707—By endless band or chain knife
    • Y10T83/7226—With means to guard the tension
    • Y10T83/7239—With means to vary distance between pulley or sprocket axes
    • Y10T83/7251—Including means to yieldably bias pulley
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T83/00—Cutting
    • Y10T83/707—By endless band or chain knife
    • Y10T83/7226—With means to guard the tension
    • Y10T83/7239—With means to vary distance between pulley or sprocket axes
    • Y10T83/7251—Including means to yieldably bias pulley
    • Y10T83/7258—By fluid means

Definitions

  • ABSTRACT A bandmill in which a bandsaw extending around two bandwheels is subjected to strain by causing the two wheels to be spread apart by a jacking system incorporating an air spring.
  • the air spring comprises a bellows unit or a rolling diaphragm air cylinder unit and may act through a linkage or directly between the frame of the bandmill and the journal of one of the wheels movable in the frame.
  • the invention relates to bandmills and in particular to an improved jacking system for applying strain to a band saw received on the bandwheels of the mill.
  • Strain is conventionally applied to a bandsaw in a bandmill by a mechanical jacking system which causes the idler and driven wheels of the mill to be separated.
  • the jacking system normally incorporates a pair of opposed and offset knife edges which engage in corresponding offset recesses in a torque bar which is biased to rotate so as to apply strain by a weight acting through a lever.
  • Such a system enables relatively constant saw tension to be maintained on the saw blade regardless of saw length changes caused by load and temperature variations.
  • a typical bandmill utilizing such a system is described in US. Pat. No. 3,158,184.
  • the invention therefore provides a bandmill comprising a frame, first and second bandwheels for receiving and guiding a bandsaw, first and second pairs of journals respectively journalling said first and second bandwheels, means fixedly mounting said first pair of journals in said frame, jacking means supporting said second pair of journals from said frame for varying the spacing of said first and second pairs of journals, said jacking means comprising a pair of jacks each independently supporting one each of said second pair of journals and at least one air spring for generating live strain in a bandsaw received on said bandwheels subsequent to the application of primary strain by operation of said jacks.
  • the air spring comprises a bellows which may be connected to a pressurized air reservoir.
  • the air spring may however also comprise a rolling diaphragm air cylinder unit.
  • FIG. 1 is a side elevation showing the general arrangement of a bandsaw incorporating a strain system according to the invention
  • FIG. 2 is a side elevation, partly in section, of one embodiment of strain system according to the invention.
  • FIG. 3 is a sectional plane view on the line 33 of FIG. 2,
  • FIG. 4 is a sectional rear elevation on the line 4-4 of FIG. 2,
  • FIG. 5 is a side elevation, partly in section, of a second embodiment of bandmill strain system according to the invention.
  • FIG. 6 is a side elevation, partly in section, of a third embodiment of bandmill strain system according to the invention.
  • FIG. 7 is a plan view, partly'cut away, on the line 7-7 of FIG. 6.
  • FIG. 1 shows a bandmill having a frame 1 including a table 2.
  • the table 2 carries a fixed lower bandsaw guide 3 and the frame 1 carries an adjustable upper bandsaw guide 4 for a bandsaw 5 extending around idler and driven bandwheels 6 and 7 respectively.
  • the driven bandwheel 7 is mounted for rotation between a pair of journals 8, one of which is seen in FIG. 1.
  • the idler bandwheel 6 is mounted for rotation between a pair of journals 9, one of which is seen in FIGS. 1 and 2.
  • Each journal 9 is carried at the end of a screwed rod 10 locked in a threaded bushing l l by lock nuts 12.
  • the bushing 11 is pivoted at 13 at the upper end of a swan neck 14.
  • the swan neck 14 extends upwardly from a ring boss 15 secured at the upper end of a tubular post 17.
  • the post 17 extends slidably through guide bushings 18 provided on the frame 1 and is bolted at I the lower end to a plate 19.
  • the plate 19 is secured by vertical spacer plates 20 to a second plate 21 mounted on a jack 22.
  • the plate 19 carries a concave bearing plate 23 on which a convex bearing member 24 at the lower end of a strain rod 25 is received.
  • the elements 23 and 24 constitute a rocker bearing and the clearance between the strain rod 25 and the tubular post 17 is sufficie nt to permit limited rocking movement of the strain rod.
  • an axial recess 26 is provided in which a cylindrical insert 27 is received.
  • the insert 27 is formed with an upwardly facing knife edge 28 which engages in a downwardly facing V recess 29 formed in a torque bar 30.
  • the journal 9 on each side of the bandmill is also provided with a recess 31 in which an insert 32 is received.
  • the insert 32 has a concave surface against which fits a convex surface of a member 33.
  • the member 33 has a downwardly facing knife edge 34 engaging in an upwardly facing V recess 35 formed in the torque bar 30.
  • the bearings 23/24 and 32/33 ensure that the load bearing knife edges self-align, provide for even distribution of load along the knife edges, and minimize friction.
  • Each torque bar 30 has a rocker arm 36 keyed thereto, the free end of the rocker arm 36 having one end of a link rod 37 pivoted thereto at 38, by means of self-aligning ball bushings and needle roller bearings.
  • the link rods 37 on each side of the bandmill extend downwardly and are pivoted at their lower ends 39 to short levers 40, also by means of self-aligning ball bushings and needle roller bearings.
  • Each of the levers 40 is connected to a position adjacent to one end of a cross shaft 41 which is joumalled for rotation at each end in bearings 42 carried on bracket plates 43.
  • the bracket plates 43 are secured to the vertical plates carrying the plates 19 on each jack.
  • the bearings 42 incorporate selfaligning rollers to permit limited independent movement relative tothe cross shaft 41.
  • the bracket plates 43 have portions 44 extending upwardly and rearwardly at an angle as best seen in FIG. 2.
  • the portions 44 are upwardly slotted from their undersides and receive in loosely interlocking engagement therewith the stepped ends 45 of a bridge member 46, as best seen in FIG. 4.
  • the loose engagement of the ends 45 in the slots also facilitates independent operation of the jacks 22.
  • a lever 47 extends rearwardly from the cross shaft 41 to a position beneath the transverse beam or bridge member 46.
  • the end of the lever 47 has a dependent pin 48 pivoted thereto at 49 and carrying a weight 50.
  • a bellows unit 51 is secured, the unit having an inlet connector 52 connected by a pipe connection 53 to a reservoir 54 of air under pressure.
  • the bellows unit 51 may be of any suitable kind, preferably having no static friction.
  • the unit manufactured by the Firestone Tire and Rubber Company of Canada Limited under the trade description Airstroke has been found suitable for this duty.
  • the lever 47 has a mercury tilt switch 55 mounted thereon suitably connected into two warning light circuits (not shown) in a conventional manner for indicating respectively excessively high or low positions of the lever.
  • a stop 56 is provided on each swan neck 14 so as to engage the upper surface of the rocker arm 36. Damage due to over extension of the bellows unit 51 is prevented by a crossbar 57 extending beneath the lever 47 and connected at its ends by chains 58 to the transverse beam member 46.
  • the bellows 51 is first pressurized to a predetermined pressure calculated subsequently to provide the required live strain in the band saw blade.
  • the two jacks 22 are next raised simultaneously until the load on the knife edges 28 and 34 act through the rocker arm 36, link rod 37 and cross shaft 41 to compress the air in the bellows 51.
  • This jacking continues until the lever 47 is lifted from the crossbar 57 into a balanced sensitive state. This state can be determined by means of the two indicator lights (not shown) operated by the mercury tilt switch 55.
  • the saw is then momentarily started to check that the saw is running correctly on the wheels, one or other of the jacks 22 being independently adjusted to provide correct running and the correct tooth projection. The saw is then ready for full operation.
  • a total strain of 24,000 pounds on a 5 foot bandmill or 65,000 pounds on a 9 foot bandmill can be developed with an air pressure not exceeding 50 pounds per square inch.
  • the weight 50 can be dispensed with, although it may be preferred to retain it.
  • FIG. 5 shows a bandwheel strain system generally similar to that of FIGS. 2 to 4 but modified in respect of the means of supplying air pressure. Similar features however, are accorded the same reference numerals and will not be further described.
  • FIG. 5 omits the bellows unit 51, the portions44 of the bracket plates 43 and the transverse beam member 46.
  • the lever 47 is further provided with an upstanding lever portion 60 to which is pivoted one end 61 of a piston rod 62 extending from an air cylinder unit 63.
  • the other end of the air cylinder unit 63 is pivoted at 64 in a bracket 65 secured to the frame 1.
  • the air cylinder unit 63 is preferably a rolling diaphragm air cylinder, for example of the kind manufactured and sold under the registered trade mark Bellofram".
  • the air cylinder unit 63 is connected by means of the connection 53 44 to the air reservoir 54.
  • FIGS. 6 and 7 show a third embodiment according to the invention.
  • the basic construction is generally similar to the assembly described with reference to FIGS. 2 to 4.
  • the same features have been assigned the same reference numerals and will not be further described.
  • the bellows unit 51, portions 44 of the bracket plates 43 and the transverse beam mem ber 46 are omitted, the remaining portions of the linkage previously described then serving only to ensure wheel stability and prevent sideways tilting.
  • Weight 50 may or may not be included.
  • the bosses 15 are provided with forwardly extending support platforms 70, the journals 9 being provided with forwardly extending reaction plates 71 immediately above the platforms 70.
  • a bellows unit 72 is secured between each platform and the reaction plate 71 immediately above it, and has a connector 73 connected by means of an air connection 74 to an air reservoir (not shown) similar to the reservoir 54 of FIGS. 2 to 4.
  • the strain on the bandsaw is effected simultaneously by means of the deadweight 50, when provided, acting through the linkage 47, 36 and by pressurization of the bellows units 72 to cause separation of the plates 71 from the platforms 70.
  • the bellows may contain an inert gas instead of air.
  • a bandmill comprising a frame
  • first and second pairs of journals respectively journalling said first and second bandwheels
  • a first pair of knife edged members each mounted on one of said jacks and engaging in one recess in one of the torque bars
  • a bandmill comprising a frame
  • first and second bandwheels for receiving and guiding a bandsaw
  • first and second pairs of journals respectively journalling said first and second bandwheels
  • a first knife edge member mounted on the support end and engaging in one of said recesses
  • rocker arms secured to and radiating from the torque bar in a direction away from said support;
  • a bandmill as claimed in claim 3 in which said air spring is connected to the cross shaft so as to resist rotation thereof by movement of said rocker arms.
  • a bandmill as claimed in claim 4 in which the air spring is connected to the cross shaft through a lever connected to and radiating from the latter.
  • a bandmill as claimed in claim 3 including a weight connected to the cross shaft so as to assist the air spring.
  • a bandmill as claimed in claim 5 in which said lever is substantially parallel with said rocker arms, and said air spring is connected to said lever at a point spaced from the cross .shaft, andsaid link means are connected to the respective rocker arms at points spaced from the respective torque bars.
  • a bandmill as claimed in claim 7 including a weight connected to said lever at a point spaced from the cross shaft.
  • a bandmill as claimed in claim 3 including a lever connected to and radiating from the cross shaft, said lever being substantially parallel with said rocker arms, and a weight connected to said lever at a point spaced from the cross shaft.
  • a bandmill comprising a frame
  • first and second bandwheels for receiving and guiding a bandsaw
  • first and second pairs of journals respectively journalling said first and second bandwheels
  • jacking means supporting said second pair of journals from said frame for varying the spacing of said first and second pairs of journals, said jacking means comprising a pair of jacks each independently supporting one each of said second pair of journals,
  • said interposed means including a rotatable member for causing such movement
  • At least one gas spring having one end fixed against movement and an opposite end so connected to the second pair of journals as to generate live strain in a bandsaw received on said bandwheels subsequent to the application of primary strain by operation of said jacks,
  • said means operatively connected to said interposed means comprising:
  • a bandr'nill comprising a frame
  • first and second bandwheels for receiving and guiding a bandsaw
  • first and second pairs of journals respectively journalling said first and second bandwheels
  • a gas spring mounted to generate live strain in the bandsaw by resiliently urging the second journals away from the first journals, and means associated with said gas spring and operatively connected to said interposed means to cause said gas spring to maintain live strain in the bandsaw and to absorb shock loads applied thereto.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Fluid-Damping Devices (AREA)
  • Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
US338895A 1973-03-07 1973-03-07 Bandmill strain system Expired - Lifetime US3905266A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US338895A US3905266A (en) 1973-03-07 1973-03-07 Bandmill strain system
CA168,788A CA1058485A (fr) 1973-03-07 1973-04-16 Systeme tendeur pour scie a ruban
AU66281/74A AU473549B2 (en) 1973-03-07 1974-03-05 Improved bandmill strain system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US338895A US3905266A (en) 1973-03-07 1973-03-07 Bandmill strain system

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US3905266A true US3905266A (en) 1975-09-16

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AU (1) AU473549B2 (fr)
CA (1) CA1058485A (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3202500A1 (de) * 1982-01-27 1983-08-04 CAE Machinery Ltd., Vancouver, British Columbia Bandsaege
US4505176A (en) * 1982-09-17 1985-03-19 Industries P. H. L., Inc. Bandmill mechanism
GB2180439A (en) * 1985-09-17 1987-04-01 Jongerius Bv Bread slicing machine
WO1988003850A1 (fr) * 1986-11-27 1988-06-02 Aktiebolaget A.K. Eriksson Agencement tendeur pour lames de scie
US5819630A (en) * 1996-05-09 1998-10-13 T.S. Manufacturing Company Bandsaw
US20060037448A1 (en) * 2004-08-23 2006-02-23 Snodgrass Howard J Jr Blade tension gauge

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US532663A (en) * 1895-01-15 hanson
US798569A (en) * 1904-01-06 1905-08-29 Charles E Cleveland Band-saw mill.
US879500A (en) * 1907-01-05 1908-02-18 Berlin Machine Works Band-saw-tensioning device.
US2729003A (en) * 1953-07-01 1956-01-03 Samcoe Holding Corp Rolling pressure control apparatus
US2973015A (en) * 1959-10-26 1961-02-28 Sabre Res Corp Bellows structure
US3810409A (en) * 1971-04-06 1974-05-14 Letson & Burpee Ltd Bandmill strain mechanism

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US532663A (en) * 1895-01-15 hanson
US798569A (en) * 1904-01-06 1905-08-29 Charles E Cleveland Band-saw mill.
US879500A (en) * 1907-01-05 1908-02-18 Berlin Machine Works Band-saw-tensioning device.
US2729003A (en) * 1953-07-01 1956-01-03 Samcoe Holding Corp Rolling pressure control apparatus
US2973015A (en) * 1959-10-26 1961-02-28 Sabre Res Corp Bellows structure
US3810409A (en) * 1971-04-06 1974-05-14 Letson & Burpee Ltd Bandmill strain mechanism

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3202500A1 (de) * 1982-01-27 1983-08-04 CAE Machinery Ltd., Vancouver, British Columbia Bandsaege
US4505176A (en) * 1982-09-17 1985-03-19 Industries P. H. L., Inc. Bandmill mechanism
GB2180439A (en) * 1985-09-17 1987-04-01 Jongerius Bv Bread slicing machine
WO1988003850A1 (fr) * 1986-11-27 1988-06-02 Aktiebolaget A.K. Eriksson Agencement tendeur pour lames de scie
US4926733A (en) * 1986-11-27 1990-05-22 Aktiebolaget A.K. Eriksson Saw blade tensioning arrangement
US5819630A (en) * 1996-05-09 1998-10-13 T.S. Manufacturing Company Bandsaw
US20060037448A1 (en) * 2004-08-23 2006-02-23 Snodgrass Howard J Jr Blade tension gauge
US7594462B2 (en) 2004-08-23 2009-09-29 Snodgrass Jr Howard L Blade tension gauge

Also Published As

Publication number Publication date
CA1058485A (fr) 1979-07-17
AU6628174A (en) 1975-09-11
AU473549B2 (en) 1976-06-24

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