US2659401A - Pressure bar support for veneer lathes - Google Patents

Description

Nov. 17, 1953 Filed Aug. 24, 1950 J. T. LATIMER PRESSURE BAR SUPPORT FOR VENEER LATHES 3 Sheets-Sheet l lav-E I 66 f INVENTOR.

w I k\\\\\\\\\\\ WEI/ll Ii/v55 2. 4.4770151 J. T. LATIMER PRESSURE BAR SUPPORT FOR VENEER LATHES Nov. 17, 1953 Filed Aug. 24, 1950 3 Sheets-Sheet 2 mmvrm d/VMIS I LIT/MEX B fflz ITTORNEYS Nov. 17, 1953 J. T. LATIMER PRESSURE BAR SUPPORT FOR VENEER LATHES 3 Sheets-Sheet 3 Filed Aug. 24, 1950 INVENTOR. Jane; 7. L/rr/MER .BYi I flTTORA/EYS Patented Nov. 17, 1953 PRESSURE BAR SUPPORT FOR VENEER LATHES James T. Latimer, Birmingham, Ala., assignor to Jackson Industries Inc., a corporation of Alabama Application August 24, 1950, Serial No. 181,295

6 Claims.

My present invention relates to an adjustable support for the pressure bar of veneer lathes and the like and has for an object the provision of apparatus of the character designated by means of which the pressure bar may be withdrawn from the log, permitting the knife of the lathe to true up the log prior to commencing the cutting of veneer therefrom, and which may also be provided with mechanism affording micrometric adjustment of the pressure bar relative to the Another object is to provide a quick and positively acting means for moving the pressure bar toward and away from the log in combination with the above mentioned micrometric adjusting means, permitting the pressure bar to be quickly and accurately set to its work, the apparatus betag so arranged that withdrawing of the pressure bar does not disturb the setting of the pressure bar when the carriage is again moved toward the log.

A more specific object is to provide a fluid pressure cylinder for moving the pressure bar supporting means and hence the bar itself toward and from the log, and to operatively mount the micrometric bar adjusting means on the support, simplifying the apparatus and assuring positiveness of operation.

Another object is to provide, in a veneer lathe or the like having a pressure bar supporting carriage, rugged, accurate and simple means to move and hold the carriage with the pressure bar thereof in engagement with the log, such means being in the form of oppositely disposed wedge blocks secured to a common axially movable member and cooperating with complementary stationary wedge blocks, together with means to move said member axially, whereby the pressure bar is engaged with a log in the lathe with very high, accurately determinable pressures which are equal throughout its length.

In the art to which this invention relates it is well known that the quality of veneer cut in a lathe depends in great'measure upon the degree of pressure with which the pressure bar engages the log. While so far as I am aware, the exact values of these pressures are not known it is known that they are exceedingly high in the cutting of certain thicknesses of veneer from certain kinds of logs. In all instances the engaging pressure should be equally applied to the log at the correct point relative to the knife, and as stated, these pressures are for the most part very high. Heretofore, many forms of adjusting means for the pressure bar have been tried. Those with which I am familiar have embodied threaded rods with gears for rotating them in synchronism, rotatable eccentrics and the like. Such apparatus has the disadvantages, among others, of inaccuracy, uneven application of pressure, excessive wear, high cost and susceptibility to mechanical failure due to the high stresses on the parts. Further, in the prior art apparatus the mechanism for retracting the pressure bar has been generally unsatisfactory for some of the reasons above mentioned.

Briefly, in my invention I mount the pressure bar carriage for sliding movement on ways in very much the normal manner. To the rear side of the carriage I fixedly mounted one or more heavy, double acting fluid pressure cylinders. The piston rod or rods of the cylinders carry members reciprocably mounted in supporting housings, the members having a tapered side. Cooperating with the tapered sides of the members are complementarily tapered wedges, keyed to an axially movable shaft. The shaft is provided with a threaded portion, preferably, though not necessarily near its longitudinal center and carrying an operating nut held against axial movement by a suitable mounting. When pressure is admitted to the forward side of the piston, the cylinder and hence the pressure bar support move toward the,

log until the piston comes chock-a-block in the cylinder. By moving the shaft axially I am enabled to move the pressure bar toward or from the log an infinitely small or an appreciable amount depending solely upon the taper of the wedges andthe total axial movement of the shaft. The pressure bar carriage may be moved away from the log by admitting pressure to the other ends of the cylinders, this being accomplished without in any way interfering with the micrometric adjustment of the pressure bar mechanism.

Apparatus embodying the features of my invention is shown in the accompanying drawing forminga part of this application in which:

Fig. 1 is a sectional plan view, somewhat diagrammatic and with certain parts broken away and showing a veneer lathe embodying my invention;

Fig. 2 is a sectional view taken generally along line II--II of Fig. 1;

Fig. 3 is a detail sectional view taken generally along line IIIIII of Fig. 1;

Fig. 4 is a sectional view taken along line IV.IV of Fi 1; Fig. 5 is a sectional view taken along lineV--V of Fig. 1;

Fig. 6 is a fragmental sectional exploded perspective view showing the axially movable shaft, certain of the supporting bearing blocks therefor and one of the wedges and cooperating blocks;

Fig. '7 is an enlarged detailed sectional view taken generally along line VII-VII of Fig. 1;

Fig. 8 is a fragmental plan view of the pressure bar indicator dial and pointer;

Fig. 9 is a view corresponding generally to Fig. 1 and showing a modified form of my invention;.

Fig. 10 is a sectional view taken generally along line x-x of Fig. 9; and,

Fig. 11 is an elevational view of one of the ad justing shims which may be employed with the invention shown in Figs. 9 and 10.

Referring now to the drawings for a better uhderstanding of my invention and more particularly to Figs. 1 to 8 inclusive, I show'my ir'iv'ention associated with a lathe embodying a supporting manner understood, the carriage l2 slides toward a and from a log l3 mounted in the lathe centers indicated at I4 and It in Fig. 1. The log is driven by means of a chain I 'I or the like from a suitable motor or the'like, not shown.

The main carriage is moved toward and from the log by means of feed screws I9 and 2|, each carrying a bevel gear 22 on one end. The gears 22 mesh with similar gears 23 carried on a shaft 24 which may be driven through a sprocket or the like 26 from any suitable source of power, not shown. As iscustomary, the maincarriage carries 'at its front the veneer cutting knife 21 which is supported in the knife support ing mechanism indicated generally by the numeral 33. The depth of cut for the lathe is determined by the infeed motion produced by the feedscr'ews 19 and 2|.

Slida'bly mounted in guides 28 and 29 in the main carriage I2 are projections 3| and 32 in the form of heavy plates. The plates 3| and32 form a part of the pressure bar carriage indicated generally by thenumeral 33, and the apparatus is so arranged that the pressure'bar carriage is movable toward and from the log l3.

The carriage 33 comprises a main base plate having welded or otherwise secured thereto upstanding vertically disposed plates 36 and-31. The plate 36 may carry a rearwardly sloping reinforcing and strengthening plate 38, while the plate 31 may carry a reinforcing plate 39 generally parallel to the plate 34. The plates 38''38 are connected to the plate 31 at intervals by vertically disposed plates 4|.

Mounted at the front of the carriage 33, namely at the side thereof adjacent the log l3, is'th'e' Plf ure bar 32. The pressure bar 42 may be in any of the several forms known in the art, ineluding the plain, rounded edge solid type. However, for the purpose of illustration I show the same as embodying the bar "with theengaging roller 43 suitably mounted for rotation in elon'- gated bearings carried in the bar '42. The bar 42 maybe held in adjusted position by means of 'a plurality of sleeves 44' screwed through the plate 36. Studs 43 pass through the sleeves N, and a" lock nut "serves to lock the sleeves against rotation. The bar 42 and hence the roller '33 are adjusted outwardly of the plate 36, hence to correctly align the same relative to the axis'of the'log. It will be understoodthat'there area 4 large number of the sleeves 44 and studs 48 pro vided so that the thrust is adequately transmitted to the carriage 33. These sleeves are accessible for adjustment through the resulting openings between the plates 4|.

Mounted on the rear side of the plate member 31 of the carriage 33 and with their axes parallel to the direction of movement of the carriage 33 are two heavy duty, double acting fluid pressure cylinders 48 and 49. The cylinders embody the usual pistons 5| and 52, heavy piston rods 38 and. and the usual seal means in the form of glands 56 and 51. For a reason later to appear the outer ends of the piston rods are reduced andthrea'd'ed' as indicated at 53 and i3. Fluid may be admitted to either end of the pistons through li'nes BI and 62.

on heavybrackets 63 upstanding from the rear side of the main carriage l2 and forming parts of the main carriage is a cross frame comprising parallel plates 64 and 68 connected by a base plate 31'. Mounted adjacent each end of the framejust mentioned, and secured to the plate 31- thereof by means of bolts 83 are bearing blocksll and 12 for supporting the end of a longitudinally movable wedge carryin member I3. In view of the fact that the mechanisms now to be described and which supports each end of the member 13 are duplicates. a description of one wiii-suflice for both. As best shown in Fig. 6, the blocks II are provided with a U-shaped opening H! for receiving the end of the member I3, which preferably is a square shaft. The blocks H are held to the base plate 31 by means of the bolts 69.

Disposed to cooperate with the blocks It in holding the member 13 therein are L-shap'ed blocks or caps'lljwhich fit against the slotted outstanding legsof the blocks H, and are held thereto'by means'of countersunk bolts 16. The members H and their respective caps I4 are spaced apart to provide aligned openings 11 and 18. Slidably fitting in the openings 11 18' a 'U- shaped block 19 having vertically elongated notches 8| in the edges of the base section and with the legs thereof parallel to the plates 6'4 and 66. Keyed to the base of the block 13 by means of projections 32 fitting in the notches BI. is a block 83 having a tapering front face 84. .Flttingnext adjacent the face 34 is a wedge block 86 'ha'vihga 'complementarily tapered face 31. The block'ti 'iskeyed' to the square shaft 13 by means of a projection-'33 disposed to fit in a slot 89"in'the shaft. The U-shaped block 19 and the shaft may slide against wear plates 19a and 13b.

' on" the opposite side of the shaft '13 are provided identical wedge'blocks 36, similarly keyed to the opposite face of the'shaft 113 and another of thetaper'blocks '83. The forwardmosttaper block 83 is keyedto a; cap 9i joining theforward ends of the legs of block 19', and secured thereto-by screws 30. The U-shaped blocks" togetherwith the'caps' 9"! thus 'forin hoiisings surrounding the endsofthe shaft 13'. The cap 3 I is provided with a' threaded hole 92' for receiving the threaded reducedehdof the'pistonrodLock nuts 03 secure tlgg caps in adj'u'sted position on the piston r s.

It will "be rioteclthatthe taper blocks and wedg'e'blocks at each end of the shaft 13 slope in the samedirection. Thus, whentheshaft "is moved: axially to the i'IEht, the -U-shaped blocks Ts'and' theireaps 8i constituting housings, move outwardly, thus movin'g'the entire pressure .har carriage '33 thrcughtnepiston rods 33 and,

all as will more fully appear. The mechanism for shifting the shaft I3 axially will now be described.

Mounted to the forward face of the plate 61 by means of bolts 94 is a U-shaped nut housing member 99. The ends of the forward legs of the housing 96 are provided with aligned semi-circular openings 91 for receiving the reduced end 98 of a split nut 99. The nut 99 fits on a threaded centrally disposed section 13a of the shaft I3 and the halves thereof are secured together by countersunk bolts, not shown. The nut 99 is also provided with a sprocket IOI, driven by a chain I02, in turn driven by a sprocket I03. The sprocket I03 is carried on the end of an output shaft I94 of a gear box I06 to which is connected a reversible electric motor I01. The motor and gear box may conveniently be mounted on the plate member 64 as shown more clearly in Fig. 4. It will be noted that the reduced ends 98 of the nut are shouldered. Nut retaining caps I95 fit about the reduced ends of the nut, and are held to the member 96 by bolts I00.

For convenience in determining the setting or axial position of the shaft I3 I may provide the indicator mechanism therefor shown in Figs. 7 and 8. To the top of the shaft I3 I secure, by means of a bolt I08, a plate I09 having gear teeth I I cut in one edge. Mounted in a suitable bearing Ii I in the frame plate member 64 is a shaft II2. A small gear H3 is fixed to the shaft H2 and meshes with the teeth I I 0.

Mounted on top of the plate 64 is a pointer I I 4. Fixed to the projecting upper end of the shaft is a rotatable disc H9 which is laid off on its upper face by means of the lines II! from a zero point as indicated in Fig. 8. By reference to the disc I I6 and the pointer H4 the axial position of the shaft I3 may be determined.

Fluid under pressure may be admitted by a four-Way valve IIS selectively to the lines GI and 92. In the manner understood for such valves. when pressure is admitted from a source, not shown, through the line IIEI to the cylinders through line BI, fluid drains back to the reservoir, not shown, through a line I2I, and vice versa when pressure is admitted to the line 62. In order to assure that there are no fluctuations in the pressure within the cylinders 48 and 49 when the lathe is in operation I may provide a pressure line I22 leading from a source of fluid under pressure not shown, to the line 62. Also, I may insert a check valve I23 in the line I22.

From the foregoing the method of constructing and using my improved apparatus as so far described may now be explained and understood. When a log I3 is first placed in the lathe it is necessary to trim off the projecting limbs, knots and the like preparatory to commencing the veneer cutting operation. In order for the knife to properly act upon the log to true it up, it is necessary to withdraw the pressure bar 42. I accomplish this by admitting fluid under pressure through the valve II8 to the pistons 48 and 49 through the line 6|. This causes the pressure bar carriage 33 to move to the right to the position shown in Fig. 2 of the drawing. The pressure bar in this position is retracted away from the log. After the knife trues up the log, fluid is admitted to the cylinders 48 and 49 through the line 62, moving the pressure bar carriage 33 to the left. The pressure is maintained in the line 92 during the veneer cutting operation. The pressure bar is now adjusted to the correct pressure against the log by energizing the motor I01,

rotating the nut 99, which as will be remembered is held against axial movement in the member 96. Rotation of the nut in a given direction moves the shaft I3 axially. If it is desired to increase the pressure on the pressure bar against the log the shaft I3 is moved to the left as viewed in Fig. l by energizing the motor I0'I'to drive the nut in the direction desired. It will be apparent that tremendous pressures between the pressure bar and log can be developed because of the wedge arrangement shown. Further, when the pressure is set, the entire main carriage I2 moves inwardly, thus cutting a continuous sheet of veneer from the log, and in nowise disturbs the amount of pressure initially set. If for any reason it is necessary to back ofl. the carriage 33 and again engage the pressure bar with the log this may be accomplished without disturbing the inicrometric pressure bar adjustment since the hydraulic cylinder acts independently of the micrometric adjusting means.

It will also be seen that the nuts 93 and threaded ends of the piston rods afford means for adjusting and truing up the entire pressure bar carriage so that the pressure bar is parallel to the axis of the log, namely, parallel to the lathe centers. By means of the threaded sleeves 19 and lock nuts til together with the studs 46 I effectively eliminate bowing of the pressure bar by supporting the same at a number of points throughout its length, thus to transmit the pressure back to the pressure bar carriage.

Referring now particularly to Figs. 9, 10 and 11, I show a modified form of my invention in which the wedge mechanism may be eliminated. The modification shown is particularly advantageous for use in smaller veneer lathes, and is somewhat less expensive to build.

As shown, the pressure bar carriage 33a and main carriage I20. are substantially identical with the one already described as are the infeed screws therefor. Instead of using two of the cylinders 48 and 49, I use a single cylinder 43a having a piston I24 and a piston rod I26. The outer end of the piston rod is pivotally connected by a pin IZEc to a clevis l2! carried by the base plate member 61a. Fluid under pressure may be admitted through the four-way valve II8a to either side of the piston through the lines 6Ia and 92a. Also, I may provide the auxiliary pressure line i22a and the check valve therefor I23a.

In order to limit the pressure with which the pressure bar 42a engages the log, I provide a pair of rearwardly extending bolts I28. The outer ends of the bolts are threaded as indicated at I29 and the bolts pass through enlarged holes I3I in the base plate member 67a. On the threaded ends of the rods I provide lock nuts I30 and a washer I32. If desired, I may insert shims I33 between the washers I32 and the frame member 61a. These shims may be U-shaped as illustrated in Fig. 11 and may be made accurately to desired thicknesses.

From the foregoing it will be seen that when pressure is applied to the cylinder 48a the car riage 99a moves forwardly until its forward motion is arrested by the bolts I28 reaching the limit of their travel as determined by the setting of the nuts I30. Since the piston rod I26 is pivotally mounted to the plate 61a there is no bending action on the piston rod during the motion of the carriage. The pressure of the pressure bar roller 43:: thus may easily be determined by properly adjusting the nuts I 30.

From the foregoing it will be apparent that I awe have devised an improved adjustable pressure bar mechanism for veneer lathes. With either form of my invention it will be understood that the cylinders are of sufficient size and the pressures therein are sufficiently great to assure the holding of the pressure bar to its work within any normal range of setting either made by the wedge mechanism or permitted by adjusting the nuts I30. With either form of the invention it will be seen that the pressure bar may be retracted easily and quickly from its work when it is necessary to do so, especially when truing up a new log. It will further be apparent that both forms of the invention are entirely practical and simple of construction and that they lend themselves to installation on existing veneer lathes without major change in the lathe.

While I have shown my invention in but two forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What I claim is:

1. In a veneer'lathe having a main frame and a pressure bar carriage slidably mounted for movement relative to the main frame toward and from the lathe centers, the improvement comprising an elongated member mounted for axial movement relative to the main frame rearwardly of the pressure bar carriage and held against lateral movement toward and from the pressure bar carriage, wedges carried by the member ad- Jacent each end thereof, a housing for each of the wedges carrying complementarily tapered surfaces engaging said wedges, means mounting the housings for movement toward and from the pressurebar carriage and holding them against movement in other directions, connections between the housings and the pressure bar carriage, and means to shift the member axially in either direction whereby the Wedges move the pressure bar carriage toward the lathe centers when the membermoves in one direction and away from the centers when the member moves inthe other direction.

2. Apparatus as deflned in claim 1 in which the axially movable member is a square shaft,

and in which the means to move the same comprises a rounded and threaded section on the shaft, a nut on the threaded section, means holding the nut against axial movement, and means to rotate the nut.

3. Apparatus as defined in claim 1 in which the connection between the housing and pressure bar carriage is in the form of elongatable and contractible mechanism.

4. In-a veneer lathe of the type having a main frame with a main carriage slidably mounted thereon for movement toward and from the lathe centers and a pressure bar carriage slidably mounted on the main carriage for movement relative thereto toward and from the centers, the improvements comprising a shaft mounted for axial movement on the main carriage rearwardly of the pressure bar carriage and held against movement toward and from the pressure bar carriage, housings surrounding the shaft adjacent its ends, means mounting the housings for sliding movement toward and from the pressure bar carriage, wedge means interposed between the front and rear sides of the shaft and the housings effective upon axial movement of the shaft to slide the housings toward or from the pressure bar carriage, power driven means for moving the shaft axially, fluid pressure cylinders embodying pistons and piston rods operatively interposed between the housings and the rear of the pressure bar carriage, and means to admit fluid under pressure selectively to opposite ends of the cylinders.

5. Apparatus as defined in claim 4 in which there is provided indicator means for determining the relative outward positions of said housings from the portion of the main carriage with which said housings are associated.

6. Apparatus as defined in claim 5 in which said indicator mechanism comprises a rotatable shaft, a gear on one end of the shaft, a rack carried by the axially movable shaft and meshing with said gear, a dial acUacent the other end of the shaft, and a pointer adjacent the dial carried by the main frame of the lathe.

JAMES T. LATIMER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Re. 6,341 Brown Mar. 23, 1875 198,404 McEachren Dec. 18, 1877 535,673 Clayton Mar. 12, 1895 1,989,386 Tallquist Jan. 29, 1935 2,348,803 Friz May 16, 1944 2,436,806 Hunt Mar. 2, 1948 2,534,671 Haumann Dec. 19, 1950 2,562,472 Miller et al July 31, 1951

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