CA1168182A - Log feed conveyor - Google Patents

Log feed conveyor

Info

Publication number
CA1168182A
CA1168182A CA000391628A CA391628A CA1168182A CA 1168182 A CA1168182 A CA 1168182A CA 000391628 A CA000391628 A CA 000391628A CA 391628 A CA391628 A CA 391628A CA 1168182 A CA1168182 A CA 1168182A
Authority
CA
Canada
Prior art keywords
chain
chainway
central portion
links
conveyor
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
Application number
CA000391628A
Other languages
French (fr)
Inventor
Robert E. Chapman
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.)
Hawker Siddeley Canada Inc
Original Assignee
Hawker Siddeley Canada Inc
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 Hawker Siddeley Canada Inc filed Critical Hawker Siddeley Canada Inc
Application granted granted Critical
Publication of CA1168182A publication Critical patent/CA1168182A/en
Expired legal-status Critical Current

Links

Abstract

CCar 53 c&us/c LOG FEED CONVEYOR

ABSTRACT OF THE DISCLOSURE

A log feed conveyor includes an elongate chainway having a longitudinally extending central portion. A pair of longitudinal running surfaces are spaced-apart by the central portion and are generally horizontal. A pair of longitudinal side walls extend generally vertically between the running surfacesand the top of the central portion. A complementary conveyor chain runs on the chainway and has a plurality of interconnected links. Each link has flanges to each side thereof which straddle the central portion of the chainway. The flanges have inner faces which slidably contact the side walls of the chainway to provide lateral stability for the chain. The flanges have bottom faces which slidably contact the running surfaces of the chainway, providing vertical support for the chain and clearance between the chain and the top of the central portion.

Description

6i8 tl) BACKGROIJND OF THE INVENTION

The invention relates to a log feed conveyor particularly suited for feeding logs through chipping cantors and high speed bandmills.

Conveyor chains and power transmission chains have been used for many years to feed logs through twin circular saws as well as tWiZI bandmills to produce sguared timbers or cants. The chain passes between the two saws, so the minimum thickness of the cant is limited by the width of the chain. The 10 chain must be substantially narrower than the thickness of the cant so the chain will not contact the saws during the cutting operation. Because of the relatively narrow chains required to permit, for example7 the cutting of four inch nominsl c~nts, the standard manufacturing tolerance and design of these chains and carrier systems have not previously incorporated a high degree of lateral 15 stability. The lack oE late~al stability in the chain resulted in lateral instability in the log, causing sawing inaccuracies. Additional allowances had to be m~de because of these inaccuraeies to avoid undersized lumber, resulting in underutili zation of valu~ble lumber fiber.

In an attempt to overcome the lack of lateral stability, ex-pensive high precision chains and chainways have been prod~ced, such as those inUnited States Patent #3,8S8,713 to Allen This system provides increased lateral stability by providing downwardly extended guiding side bars on the chain.
However, such chains do not adequately cope with the torsional forces acting on 25 ~ log during transport ~nd sawing. Because the center of gravity of the log rarely coincides with the center line of the chain, gr~vity, together with the cutting forces, exert a torsional moment acting about the longitudinal ~xis of the conveying ch~in. Because chains as disclossed in the Allen patent ride on the top o~ chainw~ys, these torsional forces cause pivotting of the chain about the top 30 surface. The reactive force is directed to the unsupported edge of the extended side link at the most extreme cantilever position from the chain barrel or othercross member which provides the resisting moment. Such twisting of the chain results in movement of the log during the CUttiDg operation and consequent s~wing inacCurQCy and w~ste of lumber.

~;6~2 (2, SUMMARY OF THE INvENrrIoN

According to one aspect of the invention, a conveyor chain is provided for running on an elongate chainway of a log feed conveyor. The 5 chainway comprises a longitudinally extending central portion with a top. A pair of longitudinal running surfaces are spaced-apart by the central portion. The running surfaces are generally horizontal when the conveyor is positioned for use.
A pair of longituc3inal side walls, each side wall being on one side of the central portion, extends generally vertically between one of the running surfaces and the 10 top of the central portion when the conveyor is positioned for use. The conveyo r chain comprises a plur~lity of interconnected links. Each of the links has flanges to each side thereof which straddle the central portion Oe the chainway. ~ach ofthe flanges has an inner face and ~ bottom face. As the chain runs on the chainway, the inner faces slidably contact the side WQllS of the chainway to 15 provide lateral stability for the chain. The bottom faces slidably contact the runnin~ surf~ces of the chainway, providing vertical support for the chain and clearance between the ehain and the top of the central portion ancl resist axialrotation of the chain about the chainway.

According to another aspect s)f the invention, a log feed con-veyor comprises the elongate chainway and a complementary conveyor chain for running on the chainway.

Dis~dvantages of prior art devices; such as that found in United States Patent #3,858,713, are accordingly overcome by providing the relatively wi~stanc~d support of the bottom edges of the flanges. The reactive forces resisting .otation OI the chain are accordingly at the maximum distance ~rom thecenter line of the chain. Rotation of the chain is therefore less likely than with prior art chains where the only support is from the central portion of the 30 chainway. ~urthermore, because rotation tends to occur about a pivot point atthe outside of the link, the angular rotQtion and hence lateral motion of the top of the chain will be much less than thflt of ~ chain which tends to pivot about an interior point. There is also a greater chance that the center of gravity of thelog and CUttiJlg forces will occur between the two outer extremities of the chain.
35 In this situation, there will be no torsional pivotting. The result is a torsionQlly z (3~

more stable chain without loss in lateral stability.

5 13RIEF DESCRIPTICN C)E~ THE DRAWINGS

Figure l is a side elevational view showing a longitudinal segment of a log feed conveyor according to an embodiment of tl~e invention;

, 10 Figure 2 is an enlarged sectional view taken along line 2-2 of Figure l;
and F;gure 3 is an isometric view, partly broken away, of a segment of an alternative chain for the log feed conveyor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

~0 Referring firstly to Figures 1 and 2 of the drawings, ~ log feed conveyor l comprises an elongate chainway 2 and a complementary conveyor chain 4 for running on the chainway. The chain 4 is continuous and only a r~
presentative number of links are shown with a corresponding length of the chain-way 2. With reference to the chain and chainway, longitudinal directions and 25 dimensions are defined as being along central axis fi of the chainway cr parallel thereto. Tr~nsverse directions and dimensions are perpendicular to axis ~ such as transverse axis 9 of the chRin shown in Figure 2i Chainway 2 has a longitudinally extending central portion 8 with 30 a top 10. The chainway has steps on each side of the central portion 8 which form a pair of longitudinal side walls 16 and 18 and a pair of longitudinal running surfaces 20 and 22.

Running surfaces 20 and 22 are spaced-apart by central portion 35 8. The running surfaces are ~lat and coplanar and are generally horizontal when 6&~
(4~

the conveyor is positioned for use as shown in Pigures 1 anci 2. Eaclh of the side walls 16 and 18 is on one side of the ~entral portion 8 and extends generally vertically between running surfaces 20 and 22, respectively, and the top 10 of the central portion when the conveyor is positioned for use as shown.

Chainway 2 has a longitudinal spline 24 received within the complementary keyway 26 of cradle 28. Cradle 28 is mounted on top of a box-section member 30, only the upper portion of which is shown in Figures 1 and 2.
A plurality of central, vertical bores 32 are spaced-apart along the length of 10 chainway 2. Each of the bores 32 is aligned with a tapped bore 34 in cradle 28 and a similar tapped bore 36 in the top of member 30. A counter bore 37 at the top of bore 32 is sized to received hend 3fi of a bolt 38. Bolt 38 passes freelythrough bore 32 and is threadedly received by bores 34 and 36 in cradle 28 and member 30 respectively. Accordingly, a plurality of bolts 3~ along the length of15 the chainway serves to conneet together the chainway, cradle 28 and member 30.
;
The eonveyor 1 also includes the conveyor chain 4 which com-prises a plurality of first links 40 interconnected by a plurality of second links 42 and a plurality of pins 44. Each o~ the first links 4n comprises a space~apart 20 pair of side bars 46 and 4~ to each side of the centrnl portion 8 of the ehainway as seen best in Figure 2. Side bars 46 and 48 have bottom portions comprising flanges 50 and 52 which are shown in Figure 2. The ~langes straddle central portion 8 of the chainway 2. Flanges 50 and 52 have inner faces 54 and 56, respectively, and bottom fnces 58 and 60, respectively. As may be seen, as the 25 chain runs on the chainway, inner faces 54 and 5~ slidably contact side walls 16 and 18 of the chainwa~ and provide lateral stability for the chain. The bottom faces 58 and 60 of the first links are planar and have coextensive widths with the running surfaces 20 and 22 of the chainway as shown in ~igure 2. The~ widths of the bottom edges of the links and of the running surfaces are sufficient to 30 provide bearing surfaces for the chain 4 and for logs carried on the chain as described below.

Each of the first links 40 has a first end 62 and a second end 6~
which overlap ends 66 and 68 of the adjacent second links 42. The second links 35 are generally block-shaped and alternnte with the first links. ~nch of the second (5) links extends longitudinally between two of the first links as seen in Figure 1 and ex$ends transversely between the side bars 46 and 48, as seen in Pigure 2, spaced above the top 10 of the central portion 8 of the chainway. Accordingly, the flanges 50 and 52 not only provide vertical support for the chain, but also provide 5 vertical clearance 70 between second links 42 and the top 10 of the central portion.

Each of the first links 40 has a pair of transverse bores 7~ and 74 extending through both side bars near ends 62 and 64. The second links 4 have bores 76 and 78 of similar diameters near ends 66 and 68 as shown in Figure2 and Figure 1. The bores in the overlapping ends of links 40 and 4~ are transversely aligned and receive one of the pins 4~. Pins 44 are rotatably re-ceived within bor~es 76 and 78 in links 42 and are welded at the outer ends to side bars 46 and 48 to provide a hinged connection between adjacent ends OI the firstlS and second linksO

The side bars 46 an~ 48 have upwardly projecting shalp teeth 80 and 82, respectively, on the tops thereof. These teeth are adapted to penetrate and hold a log carried on top of the ehain 4 as the chain runs longitudinally along 20 the chainway 2. Forces, such as force F shown in Figure 2, caused by curvature of the log and the sawing operation tend to cause rotation of chain 4 about longitudinal axis ~ or a parallel axis. In the log feed conveyor disclosed in United States Patent #3,&58,713 to Allen, such rotation is countered only by wear blocks contacting the upper wall oP the chainway which is equivalerlt to the top 10 of the 25 central portion 8 of the present invention. By comparison, as illustrated in Figure 2, the reactive force RF for log Peed conveyor 1 is ~t the outside of thechain, increasing the ~noment resisting rotation. Unlike the Allen p~tent, the side bers of the present invention slidably contact running surfaces 20 and 22 of the chainway, providing wid~stanced vertical ~upport. The clearance 7 0 30 between the chain and the top 10 of the central portion 8 o~ the chainway, means th~t there is no tendancy for the chain to rotate about the central portion as occurs in the Allen patent. At the same time, the present invention retains the lateral stability brought about by the sliding contact of inner Pa~es 54 and 56 with the side walls 16 and 18 of centrQl portion 8.

~6~
(~) Figure 3 shows a chain 4.1 which is a variation of chain 4 of Figures 1 and 2 and runs on a similar chainway 2. Ch~in 4.1 is adapted to hold ~log 84 which has a spline 86 formed along the bottom thereof by chipping prior to the sawing operation. This method of log sawing is used on log sallving machinery 5 sold under the trade rnark CHIP-N-SAW. C:hain 4.1 is similar to chain 4 in most respects with chain ~ having second links 42.1 with bores 76.1 and 78.1 at each end thereof. Links 42.1 are hingedly connected to first links 40.1 by a plurality of pins 44.1. The bottom portions of first links 40.1 are similar to those of links 40 in Figures 1 and 2. Howeverg in lieu of teeth 8û and 82 of the first embodiment, 10 slde bars 46.1 and 48.1 are extended upwardly to form top flanges 88 and 90. As may be seen in the figure, the top flanges form a complementary channel for receiving spline 86 of the log 8~1.

Both embodiments OI the invention offer significant advantages 15 when compared with chains such as those in United States Patent #3,858,713.
Since rotation tends to occur about a pivot point at the outside of the side bars, the angular rotation and hence lateral motion of the top of the chQin will be much less than that of a chain which tends to pivot about a point between the side bars. This means that there is less lateral deviation of the log whether it is 20held by the teeth of the first embodiment or between the top flanges oP the second embodiment. It will also be appreciated that, due to the wider stance of the improved chain, there is a greater chance that the center of ~ravity and of the cutting forces will occur between the two outer extremities of the side bars.
In this case, there will` be no torsional pivotting occurring. The result is a 25 torsionally more stable chain without loss in lateral or vertical stability.

Claims (12)

(7) WHAT IS CLAIMED IS:
1. A log feed conveyor comprising:

an elongate chainway comprising:

a longitudinally extending central portion with a top, a pair of longitudinal running surfaces spaced-apart by the central portion, the running surfaces being generally horizontal when the conveyor is positioned for use, and a pair of longitudinal side walls, each said side wall being on one side of the central portion and extending generally vertically between one of the running surfaces and the top of the central portion when the conveyor is positioned for use; and a complementary conveyor chain for running on the chainway, the chain comprising:

a plurality of interconnected first links, each said first link having flanges to each side thereof which straddle the central portion of the chainway, each of the flanges having an inner face and a bottom face so, as the chain runs on the chainway, the inner faces slidably contact the side walls of the chainway to provide lateral stability for the chain, and the bottom faces slidably contact the running surfaces of the chainway, providing vertical support for the chain, clearance between the chain and the top of the central portion and resisting axial rotation of the chain about the chainway.
2. A log feed conveyor as claimed in Claim 1, wherein the chainway has steps on each side of the central portion forming the side walls and the running (8) surfaces.
3. A log feed conveyor as claimed in Claim 1, wherein the running surfaces are flat and coplanar.
4. A log feed conveyor as claimed in Claim 1, wherein the first links of the chain comprise spaced-apart side bars to each side of the central portion of the chainway, the flanges comprising bottom portions of the side bars.
5. A log feed conveyor as claimed in Claim 4, wherein each of the side bars has a top and a sharp tooth on the top for penetrating and holding a log.
6. A log feed conveyor as claimed in Claim 4, wherein the chain further comprises a plurality of second links alternating with the first links, each of the second links extending longitudinally between two of the first links and extending transversely between the side bars of the first links over, and spaced above, the top of the central portion of the chainway,
7. A log feed conveyor as claimed in Claim 6, wherein the second links are block-shaped.
8. A log feed conveyor as claimed in Claim 6, wherein adjacent first and (9) second links are hingedly connected by pins.
9. A log feed conveyor as claimed in Claim 8, wherein the side bars of each said first link and each adjacent second link have overlapping ends with transversely aligned bores for receiving the pins.
10. A log feed conveyor as claimed in Claim 9, wherein the bores and pins extend transversely through the links.
11. A log feed conveyor as claimed in Claim 1, wherein the bottom faces of the links and the running surfaces are coplanar and have coextensive widths sufficient to provide bearing surfaces for the chain and logs carried by the chains.
12. A conveyor chain for running on an elongate chainway of a log feed con-veyor, the chainway having a longitudinally extending central portion with a top, a pair of longitudinal running surfaces spaced-apart by the central portion, the running surfaces being generally horizontal when the conveyor is positioned for use, and a pair of longitudinal side walls, each said side wall being on one side of the central portion and extending generally vertically between one of the running surfaces and the top of the central portion when the conveyor is positioned for use, the conveyor chain comprising:
a plurality of interconnected first links, each said first link having flanges to each side thereof which straddle the central portion of the chainway, each of the flanges having an inner face and a (10) bottom face so, as the chain runs on the chainway, the inner faces slidably contact the side walls of the chainway to provide lateral stability for the chain, and the bottom faces slidably contact the running surfaces of the chainway, providing vertical support for the chain, clearance between the chain and the top of the central portion and resisting axial rotation of the chain about the chainway.
CA000391628A 1981-08-03 1981-12-07 Log feed conveyor Expired CA1168182A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US28918281A 1981-08-03 1981-08-03
US06/289,182 1981-08-03

Publications (1)

Publication Number Publication Date
CA1168182A true CA1168182A (en) 1984-05-29

Family

ID=23110397

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000391628A Expired CA1168182A (en) 1981-08-03 1981-12-07 Log feed conveyor

Country Status (1)

Country Link
CA (1) CA1168182A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4886156A (en) * 1985-04-19 1989-12-12 U.S. Natural Resources, Log Boss Systems Division Log conveyor system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4886156A (en) * 1985-04-19 1989-12-12 U.S. Natural Resources, Log Boss Systems Division Log conveyor system

Similar Documents

Publication Publication Date Title
US3356205A (en) Log conveyor
FI67801B (en) SAETT OCH ANORDNING FOER ATT HANTERA VANKANTADE BRAEDOR
US4993996A (en) Chain magazine for shop machines
US4697487A (en) Adjustable cable driven carriage system and method
US4816010A (en) Sprocket with radial clearing means
US3762047A (en) Cutter bar with speed tip
US3858713A (en) Log feed conveyor for bandmill
US4628781A (en) Lumber mill system
CA1168182A (en) Log feed conveyor
US3444907A (en) Saw chain
US4886156A (en) Log conveyor system
US4269303A (en) Wood conveyor apparatus
CA2349805C (en) Link for sharp chain conveyor
CA1205358A (en) Device for severing round timber
CA1051322A (en) Feed works for rotary ring log barkers
FI83847C (en) ANORDNING FOER STYRNING AV BLOCK SOM MATAS TILL EN BEARBETNINGSMASKIN.
US799836A (en) Twin-circular-saw mill.
JP2714956B2 (en) Sawmill
CA1075133A (en) Infeed and outfeed apparatus for woodworking machines
JP4339794B2 (en) Timber felling machine feeder
FI97111C (en) Wood feeding device for a mobile woodworking machine
US3100514A (en) Log debarker feed apparatus
SU960010A1 (en) Multisaw arrangement for log cutting
NZ211549A (en) Conveyor chain trackway,wear plates and wear compensation
SU1042995A1 (en) Apparatus for group cutting to length of timber

Legal Events

Date Code Title Description
MKEX Expiry