US2720898A

US2720898A - Veneer lathes

Info

Publication number: US2720898A
Application number: US323776A
Authority: US
Inventors: Bush John Thomas; Jenkins Leslie August Westover
Original assignee: Individual
Current assignee: Individual
Priority date: 1952-10-07
Filing date: 1952-12-03
Publication date: 1955-10-18
Anticipated expiration: 1972-10-18
Also published as: GB699569A

Description

1955 J. T. BUSH ET AL VENEER LATHES 2 Sheets-Sheet 2 Filed Dec. 3, 1952 ,4 5x. as .9. 14/. JE/VK/N-S United States Patent 2,720,898 VENEER LATHES John Thomas Bush, South Woodford, London, and Leslie Augustus Westover Jenkins, Putney, Londpn, England Application December 3, 1952, Serial No. 323,776

6 Claims. (Cl. 144-215) This invention relates to veneer lathes and has particular reference to the construction and operation of the spur knives used for edge trimming or other longitudinal cutting of the veneer as it is cut off the log. These spur knives are mainly employed for removing outside margins where the wood is blemished owing to shakes or clefts in the log, and generally to ensure continuous parallel longitudinal edges on the sheet of veneer determining the width of the sheet.

Hitherto the spur knives, one at each side between the lathe centres, have been bolted to the working head structure of the machine which feeds the veneering knife, and as occasion necessitates (such as when a shake varies in the extent to which it encroaches into the length of the log at different distances from the centre axis) the bolts are loosened and the spur knife shifted along its carrying structure, after which it is re-bolted in its new position.

The object of the invention is to facilitate the adjustment of the spur knife, and enable this adjustment to be quickly carried out without recourse to loosening and refixing bolts or equivalent securing means.

According to the said invention a veneer lathe is provided with a spur knife carriage mounted in a slideway on part of the working head structure so as to be adjustable on the structure parallel with the axis of the lathe centres, in combination with means remote from the carriage to shift it along the said slideway, and means to move the knife in the carriage to and from the workpiece.

In order that the said invention may be readily understood an embodiment will be described, by way of example, with the aid of the accompanying drawings in which:

Figure l is a sectional side view of a lathe to which the invention has been fitted;

Figure 2 is a face view of part of the working head carrying the invention, looking in the direction of arrow A in Figure l; and

Figures 3 and 4 are respectively sections on the lines III and IV of Figure 2.

Referring to Figure 1, a typical veneer lathe is depicted comprising a bed 1, a driving gear easing 2, from which one of the lathe centres extends to carry the log 3, and a working head comprising the veneering knife casting 4 and its knife 5, and the pressure casting 6 which is eccentrically adjustable about the shaft 7 in relation to the lower casting 4, as well known. The complete working head including the two main castings 4 and 6 is arranged to be fed to and from the workpiece 3.

At each side of the pressure casting 6 there is mounted a spur knife 8 in a carriage 9, and the knife is adapted to be slidably pressed through the carriage into the log against the resistance of a compression spring 10 to provide edge trimming or other longitudinal cutting of the veneer to be cut off the log. In the illustrated example (see Figure 2) the spur knife 8 is fixed to and alongside a spring plunger 11 associated with the said spring 10 so that the knife can rise and fall with the plunger. The

2 working head member 6 is adjusted so that the knife 8 penetrates the workpiece a requisite distance when it has been pushed into its operative position by pressure on the plunger 11.

To press the spur knife 8 into its operative position, a hand lever 12 is employed. This is pivoted to the pressure casting 6 at 16 and is linked at 13 to a plate 14 secured to a cam bar 15. The latter is fixedly carried on a shaft 17 rotatable on the relatively fixed structure 6 parallel to the slideway bar 20 hereinafter described. When the hand lever 12 is pulled down, the lower edge of the cam bar 15 is moved down as the shaft 17 partially rotates sufficiently to press on the spring plunger 11 to push the spur knife into its operative position. The lever 12 has a locking catch 18 working on a toothed quadrant 19. By releasing the catch 18 the knife is permitted to retract from the workpiece. A single operating lever 12 may be employed to control two spur knives 8, i. e. one at each side of the lathe.

The carriage 9 is adapted to be slidably adjusted to a requisite position across the working head, and for this purpose is mounted in a slideway formed between a bar 20 and the face of the head member 6, the slideway lying parallel with the axis of the lathe centres. The carriage 9 is secured to the ends 21 of a cable 22 passing around an operating wheel 23 carried by a bracket 28 and thence around guide wheels 24. The

wheels

23 and 24 may be grooved pulleys when a wire, leather or other cable is employed, or they may be toothed wheels if a chain is used in place of a cable. The operating wheel 23 is turned by a handle 25 secured thereto, and this causes the cable to pull the spur knife carriage towards one or other end of the slideway according to the direction of rotation of the wheel.

To lock the wheel 23 in a selected position there is combined therewith a fixed toothed edge disc 26 coaxial with the wheel, and the handle 25 is pivoted at 27 and made with a knife edge to take between a selected pair of teeth on the disc 26. The disc is preferably furnished with graduations corresponding with the teeth which indicate the position of the spur knife and its distance from another spur knife on the other end of the working head member 6.

In a modification the wheel 23 may be operated by power, e. g. by a hydraulically operated piston under the control of the operator at any convenient position.

In operation, the spur knife 8, or each of a pair of spur knives, is adjusted along the axis of the pair of lathe centres to remove the required outside margin of the veneer being cut by releasing the handle 25 from the fixed toothed edge disc 26, thereby releasing the operating wheel 23 for rotation by the handle 25. Such rotation of the operating wheel 23 causes the cable 22 to pull the spur knife carriage 9 towards one or other end of the slideway 20 according to the direction of rotation of the wheel 23. When the spur knife has been brought to its required position along the axis of the lathe centres, the handle 25 is again engaged with the fixed toothed edge disc 26 to positively lock the spur knife in such position. The spur knife is then brought into engagement with the workpiece by releasing the locking catch 18 from the toothed quadrant 19 and pulling down the lever 12 to rotate the cam bar 15 whereby the plunger 11 is moved against the action of the compression spring 10 to push the spur knife into its operative position, the locking catch 18 again being allowed to engage the toothed quadrant 19. Conversely, when it is required to withdraw the spur knife from its operative position, the locking catch 18 is released from the toothed quadrant 19 and the lever 12 is raised, thereby rotating the cam bar 15 and allowing the compression spring 10 to withdraw the lunger "11 "and'spur "knifeaway from the "work iece, the locking catch 18 again being engaged with the toothed quadrant 19'. I

We claim: 7

l. Aveneer lathe including 'aworking head structure, a snueway onpart of said structure, a spur knife carriage mounted in said slideway so as to be adjustable on the Working head structure in a direction parallel with the aiiis of the lathe centres, in combination with manually eonfrollable means remote from the carriage to shift it along the said slideway, manually releasable means for securing said carriage in any required position to which has been adjusted'along said axis, and means to move the knife in the car'r'iaget'o'and from the 'wor'kpiece'carried between the lathe centres.

f 2 A veneer 'lathe'iricluding 'a working head structure, aslideway on'part of said structure, a spur knife carriage mounted on said structure so as to be adjustable on the working 'head structure in a direction parallel with the zii'ris'bfthe lathe centres, in combination with a manually controllable operating wheel carried by the working head structure, guide wheels located respectively near the ends of the slideway, a cablehavingits ends secured'to the'said spur "knife carriage and passing around said operating wheel and thence around'the side guide wheels, said cable being'adapted to pull the spur knife carriage towards one brother end of the slideway according to the direction of rotation of the operating wheel, a 'fixed toothed edge disc mounted coaxially with the operating wheel, a handle adapted t'o'be locked between a selected pair of the disc teeth to secure said carriage in any required position to 'which'ithas been adjustedalong'said axis, and means to move the knife in the carriage to and from the workpiece carried between the lathe centres.

' 3. A veneer lathe accordingto claim '2, wherein 'there 'ar'etwo spur knife carriages and their respective knives mounted on the working head structure, and wherein the fixed toothed edge disc is furnished with graduations indicating the distance between the two spur knives.

4. A veneer lathe including a working head structure,

"a 'slideway'on'p'artof said structure, a spur knife-carriage mounted in said slideway so as to be adjustable on the working head structure in a direction parallel with the axis of the lathe centres, in combination with driving means remote from the carriage to shift it along the said slideway, said driving means being manually controllable, manually releasable means for securing said carriage in any required position to whichithas been adjusted along said axis, and meansto move the knife in the carriageto and from the workpiece carrie'd between the lathe centres.

5. A veneer lathe according to claim 2, wherein the means for moving the spur knife in the carriage to and from the workpiece carried between the lathe centres comprises a cam bar mounted on the working head structure parallel with the slideway, a plunger connected to the spur knife, a spring to press the plunger against the cam bar, and means to rotate the cam bar to press the knife on to the workpiece against the action of said spring.

6. A veneer lathe according to claim 2, wherein the means for moving the spur knife in the carriage to and from the workpiece carried between the lathe centres comprises a cam bar mounted on the working head structure parallel with the slideway, a plunger connected to the spur knife, a spring to press the plunger against the cam bar, and means to rotate the cam bar to press the knife on to the workpiece against the action of said spring, a hand lever pivotally mounted on the working head'structure andlinked to the cam bar to bring about rotation of the latter, and co-operating latch elements on the working head structure and hand-lever to retain the latter in an adjusted position.

References Cited in the file of this patent UNITED STATES PATENTS 113,651 Gray, Jr Apr. 11, 1871 1,655,348 Wester Jan. 3, 1928 1,849,928 Huestis Mar. 15, 1932 2,328,545 Bukowsky Sept. 7, 1943 2,634,772 Dell, Jr. et a1 Apr. 14, 1953