US2539742A - Veneer defect cutting machine - Google Patents

Description

Jan. 30, 1951 E. H. JACOBSON VENEER DEFECT CUTTING MACHINE Filed March 51, 1945 2 Sheets-Sheet 2 Patented jan. 30,

N'ITED STATES PATENT ()FFICE 2,539,742 w I V VENEER DEFECT mime means Elmer H, Jacobson, Lebanojm breg-g,aesigner i6 CascadesjPlywood Corporation, Portland, Oregi, a corporationofDelaware Application March-31, 1945, Serial No; b85949 Claims. (c1. ire-2) It is very desirable that the surface plies of plywood be free'of defects, such as knots and pitch pockets. Plywood is made ordinarily in rather tice in the coniferous plywood industry to cut out defective areas from veneer sheets which are to be used as surface pliesof pywood, and to insert patches in the apertures thus formed prior to fabrication of the plywood. V

Machines have been developed for removing the defective areas, and other machines are available for inserting patches. The Gragg Patent No. 2,071,519, issued February 23, 1937, for example, shows a machine of this general type. The present invention relates to improvements in machines for cutting holes in veneer to eliminate knots, pitch pockets and the like. p r

Defect cutting machines form an aperture in a veneer sheet of a size and shape to receive a standard patch. The particular aperture cut by machines of the type to which my invention pertains is of substantially double circular segmental shape, which I shall term biconvex. The edges of this aperture are inclined inwardly and down-. wardly and meet to form an angle at each end of the aperture.

One of the principal difiiculties which has been experienced with defect cutting machines of this type is their inability to make consistently a clean cut through a veneer sheet without stripping fibers of the Wood beyond the aperture, especially at its end at which the cutters run out.

A principal object of my invention, thereforejs to construct a machine which will cut the margm of the aperture in the veneer sheet cleanly so that it leaves the wood around the aperture intact. This object is accomplished in two ways, namely, by improving the mounting for the holddown shoe which cooperates with the cutter head, and by controlling movement of the cutter head relative to the veneer sheet, while the cut isbeing made, in a manner such that it will cut more efiectively near completion of its stroke.

An advantage of my machine is that the structure employed for accomplishing the above object need not becomplicated'. The holddown shoe is mounted so that it can be adjusted conveniently for the purpose of compensating .for wear occasioned by the use of the'machine, enabling the effectiveness of the shoe to bemaintained over an extende'd'per'iod.

cantilever supportincluding spaced horizontal .b'eams l'l, preferabl'y o f channel shape, which 1 The various advantageous .characteristics of my machine will be pointed outingifeater detail in the following particular description of the embodiment of mymvenaon which I now prefer.

, Figure 1 is a front elevation view of the defect cutting machinajan'd Figure 2 is a side elevation view of the machine, with parts broken away along line2,2 of Figure 1. I

Figure 3 is a vertical sectional view through the cutter stroke controlling cylinder of the machine,

Figure 4 a vertical sectional view through the work table and ho 1ddown shoe showing a portion of the cutter head in' elevation. Figure 5 is a plan view of an end portion of the holddown shoe, the balance of such shoe and other parts beillg broken away.

, Figure 6 is a sectionalview through the holddown shoe and its mountings taken on line 66 of Figure V d typical machine to which my invention may be i'pplied, as illustratedin the drawings, in-

, clud'es a, table! on which a veneer sheet V is laid. Thistable hasan aperture I!) in it located immediately below, the vertically movable cutter Such" cutter. head is suspended from have corresponding endscarried by a post E2. The adjacentend's of these beams which are gen" e rally above the cutter head 2 are interconnected by abridgi'ng end plate i3.

The .cutterhead 2', is mounted directly on the axle 2'0journa'led in'a'bearing 21 which is secured to the under side of a tilting bar 22. This bar rocks about a horizontal pivot 23 spaced a substantial distance from bearing 21, and the pivot is carried by" the lower end of alplate i i secured toa'nd depending froma'b'e'am I! of thecantilever ned a The" vertical disposition o fthe cutter head may thereforeberegulatedfby controlling the degree of tilt of bar 22 ab out its pivot. The cutter head maye ariven rotatively b an electric motor 24 mounted on bar 22; atjfth'e side of pivot 23 opposite"the cutter head' 'bearing 2i. [Pulleys on the m tal; shaft essentials-cutte head sha ft 25c may be interconnected byabelt 25pre fe'rably of the V type; This he neednothav any special tightiier arrangement beca se its length does net change as the cutter head is raised and lowered, sincebotli'fthe incident thecutter head shaft e ltirig bar 212 As the cutter :head is le w ere d the motor will swing upward, and

western, in See SawfaShiOn,

The cutter head in side elevation may be of cruciform shape as shown in Figure 1. Each f its arms has secured to it a blade 26, preferably of ogival contour. When these cutters, moving in an arcuate path, pass through a veneer sheet V they cut a biconvex aperture, the edges of which are inclined inwardly and downwardly.

In order to hold the veneer sheet firmly during the cutting operation a holddown shoe 3, having in it a central opening to-receive the cutter head, is arranged to be pressed down against the veneer sheet around the zone to be cut. This shoe must, of course, be raised and lowered generally in synchronism with the upward and downward movement of the cutter head in order to clamp and to release the veneer sheet at the proper time. The shoe is therefore supported by a hollow frame 3|] having a transparent door 3| to protect the operator from inadvertently touching the cutter head. This frame is guided for vertical movement by spaced guide rods 32 slidably received in bearings mounted on the front face of the support plate l3. A crosshead 33 interconnects the upper ends of the guide rods and has a lug 34 projecting rearwardly from it above such plate.

Reciprocation of crosshead 33, and consequently frame 352 and its shoe 3, is effected in synchronism with upward and downward movement of the cutter head by a rod 2'! having its upper end bearing slidably in a lug l3 projecting rearwardly from end plate I3. This bearing and lug 34 of the crosshead are disposed in alignment so that, when the end of bar 22 carrying the cutter head swings upward, rod 21 will be pushed upward to engage its upper end with the lug, thus to raise the crosshead, guide rods 32 conected to it and frame 36.

As bar 22 is swung downward to lower the cutter head, rod 2'! also will be drawn downward. The weight of frame 30, guide bars 32 and crosshead 33 will tend to slide their assembly downward as the supporting force of the rod is removed, but in addition a substantial downward force will be exerted on the crosshead by a spring 35 having its upper end connected to the crosshead and its lower end to a lug 28 projecting forward from rod 21. After shoe 3 has engaged sheet V firmly the cutter head may be moved downward farther, but the shoe cannot continue to move in synchronism. As rod 2? and its lug are drawn downward positively by bar 22 after the shoe bears on the veneer sheet, spring 35 will stretch as it exerts an increasingly greater pull on crosshead 33 to augment the pressure of the shoe on the sheet to be cut.

Mechanism for tilting bar 22 is under the control of the operator, so that the cutter head may be lowered when it is in registry with a defect in the veneer sheet. Such mechanism includes an upright rod 4 having its lower end pivoted to the end of bar 22 behind the cutter head. The

upper end of this bar is connected by a universal joint to one end of a lever 4| tiltable about a pivot 42 which extends through the central portion of such lever and is mounted in a base 43 supported from the support beams II.

The opposite end of lever 4| is swung by a compressed air or steam cylinder and piston 44 having their connecting rod 45 bearing upward against the lever. The lever and piston are re turned into the position corresponding to the upper position of the cutter head by a tension spring 46 interconnecting the lever and the base 43. To relieve rod 4 from the necessity of returning the cutter head to its upper position, a tension spring 4 41 is interconnected between a beam II and a lug 29 integral with and projecting beyond the end of bar 22 which carries the cutter head bearing 2|.

The structure described thus far is not novel. My invention is particularly concerned with the adjustment and control of such mechanism for the purpose of producing a cleancut aperture in the veneer sheet, and in particular to prevent fibers of the wood at the outrunning end of the aperture being stripped out, instead of being severed cleanly. In order to accomplish this result with certainty I have found it desirable to locate the veneer sheet holddown shoe 3 so that the margin of its aperture 36 lies closely adjacent to the upwardly moving cutter blades 26 to serve as a chip breaker, and also to move the cutter head downward sufficiently slowly with relation to its rotary speed to enable its cutters to effect a proper cutting action, rather than a tearing action. For the machine to be operated at an economical speed, however, the cutter head should not be depressed throughout its entire stroke at a speed as slow as is desirable during the final portion of such stroke.

As the aperture is cut in the veneer sheet V, held down onto the table I by the shoe 3, the sawdust particles are drawn upward through frame 30 into a suitable suction conduit (not shown) connected to it. The abrasive action of the wood particles as they are pressed by the cutters 26 against the sides of the aperture 36 gradually enlarges this aperture so that its sides no longer lie closely adjacent to the cutters. Because of this wearing action on the sides of the aperture in the shoe its central portion 31 is customarily made removable, such as being formed of Babbitt metal. When the aperture becomes very badly worn, therefore, this central section may be melted out and a new portion cast in place having an aperture of the proper size.

It has been found that the sides of aperture 36 wear sufliciently rapidly so that after a period of use even as short as one day the aperture, especially at the end from which the cutters emerge, namely at the right in Figure 4, has become enlarged sufiiciently so that the chip cut by the cutter head is not broken cleanly, and iibers are stripped from the upper surface of the veneer sheet beyond the end of the intended aperture. Since the upper side of the veneer sheet is its face side, the result is that the cutter head has cut out one defect, such as a knot or pitch pocket, only to form another defect, namely the stripped depression. Prior to my invention the only remedy for this situation was to replace the Babbitt metal center portion 31 of the shoe 3 almost every day of operation, which obviously is impractical. Consequently the practice was to patch by hand such defects as were caused by the aperture-cutting operation, and to repair the shoe 3 only when the aperture 36 had become so enlarged that a considerable proportion of the veneer apertures were defective.

I discovered that, because the margin of the veneer sheet aperture was well supported from below at its left end by the table I, as seen in Figure 4, and the cutters 26 were moving downward, it was not necessary for the margin of the shoe aperture to lie very close to the cutters to enable them to produce a clean out. At the right end of the aperture being formed in the veneer sheet, however, the cutters press the sheet upward away from the table and against the holddown shoe 3. At this location it is necessary for the shoe -shown in'detail'in Figure 3. It includes. a-'hy-- "draul-ic damping cylinder receiving. a; piston-:50.

aperture ina'rgintotli osly'aloiig'side the fiath i f thefcutter'sfassho' o-lioldthe veneershee't 'firmlyjin opposition to the upwara force of the cutter head and to break the chip near mompletion ofthe out.

For this purpose I provide a support -for the holddown shoe which enables it dice-adjusted lengthwise "so that, despite any enlar g'ement of its aperture, its margin will lieclosely alongside the V path of the upwardly-moving cutters at the right in-Figure 4, although there 'inay be a' considerable space'between 'the path of theidownwardly moving cutters and the a'perture' vvallfat the left end of the aperture without detriment. In order to suppcrt tneence ror uh 'adjustment any er eanscs typesc stmoti'on connections "may be empieyedgpro 'that theyemaintain accurately the "align-merit er -the s'hoe aperlture relative to the cutter head- 2.

-The particular 'sho'e supporting i'rnechanism shown includes'angle bars 38 secured to opposite sides of frame Sir-so that-their horizontalxflan'ges 'lie'flush with the bottom "edge "of the frame. These flanges areslotted' along. lines i'perpen'dicularto" the" upright flanges er 3 suchiiangles, :to receive' shoe clamping bolts '391'scre'wed into? tapped hoes' in the'respective' en'ds of the shoe 3. Such bolts may fit in-their grooves sufiiciently-fclosely to position the shoe accurately, but "preferably the horizontal flanges of angles 38 have small downwardly projecting lugs 38" constituting keys whichfit snugly ina keyw'ay 3' formed in-the upper sideof-the shoe at'each end toposition it laterally.

Instead of requiring the shoe 3-tobe replaced} or the Babbitt metal insert 31' to-be recast every day, my construction enables the'shoe to be shifted toward the left in Figure 4 until the: sides of its aperture36 at its ri'ght end 'justwclearthe path of cutters '26,- such adjustment :being made several timeseach day, ifdesired. When the increased clearance thus producedat the-leftend of the shoe aperturehas becometoo'great, of course, after the shoe has been shifted endwise repeatedly, the Babbitt metal insert' 31: may be 1 recast. I

While, as described, the disposition-ofshoe 3 to constitute an effective chip breaker is'very important, the cutter should nevertheless be moved downward slowlyn'ear the end of its-stroke to cutproperly, since the speed-of cutter head rotation should not be excessive. It is not neces- "sary, however, for the cutter head-"to move" at such a slow speed throughout its entire downward stroke. Because it is preferable not to rely 'upon the operator to regulate the "speed -manually to produce the desired result, I" have provided an'automatic control to effect downward movement of the cutter head-while cutting, at a progressively decreasing rate; and finally to bring it to a stop. The cutter head must not be allowed to move downward too -far, because it would form an ape'rtureinthe veneer sheet V larger than the patch-which it is to receive, and its bad'es'would cut into the convergent end surfaces of apertu're"36 in shoe 3, making it too large to cooperatelproperly with the cutters as a chip breaker.

The automatic stroke 'control mechanism' is The' piston rod- 5 I. is connected "bya universal joint 52 toan' adju'sting-screw 53= threadedisin -lever 4|. "Such's'crew -may belocked: in any 'adwjusted 'po'sition' :by the locknut which nmay 6 have an operating handle e55 rproje'ctingsfromeit for ease of operation.

"A iby+pass massage 6 alongside zthe-ecylindeir 5 extends from a location-rbelow arpluralityiof ibleed or metering orifices .69, 161,562 and :6e,1:spaced man of the cylinder, upward :above a retum orifice :64, '1 which is 5 located in the-cylinder wall :above I the uppermost position of the .upp'er surface of piston ifiil. The :piston'is; normally 2 urged upward by aspring tit-engaged betweentherlower "end of cylinder 5 "and .aifiange 51aon:the:piston rod :i5l SpaQed" S1i:g'1Tb1y?b810W thGEOVEEI'ESUIffiGBKOf the piston. Above this flange is an annularrclack valve '58 controlling the fiow of'liqnid through one or more passages -59 extending axially through the piston outwardly of piston rod 5.5.1.. Thepiston rod projects downward within spring 56 far enough to prevent thespring bucklinggand. additionally to serve as-a positive "stop :for .thepiston and rod, which is "completely enclosed and. protected by the cylinder 5, and hence itsaccuracy cannot be alfected adversely by an accumu lationof dirt or sawdust between its cooperating parts. Nevertheless the terminal lower-:position of the cutter head is readily adjustable by-raising or lowering the "position ofleven-Alrelative to the piston rod by rotation of. screw 53.

As previously stated, the airor'steamgcylinder and piston 44 press upward on the left encl' of lever M as seen in Figure 2 to depress the-right end of that lever, and consequently to moverpush rod 4 and the cutter head downward. =By: reason of the interconnection shown in---Figures 2- and 3, piston rod 5! would be moved downward simultaneously. The pressure of piston-50 ion the liquid below it in cylinder 5, caused by -,such downward movement, will immediately move clack valve ring-58 upward to close pistong-passages 59, thus trapping the liquidin the-lower end of cylinder 5 except as it may travel through Icy-pass 6 to the upper-side of the piston. -Until the lower side of the valve ring reaches the upper port 60 liquid will'be displaced through .-all of holes 60, 6!, 62 and 63, through passage-6 and into the upper end of cylinder 5 through port; 64.

Because of the substantial aggregate size ofthe several lower ports the transfer of liquid through the by-pass from the lower end to the upper end of the cylinder will be reasonably fast at first, and consequently the downward travel of piston 50 and of cutter head 2 will be at a comparatively rapid rate, at least until the cutters have started to cut the veneer sheet. Further downward movement of the piston will cause it to close first portBll, somewhat throttling the flow of fluid through the by-pass, then successively ports GI, 62 and 63. As each port is closed the flow area for passage of liquid through the by-pass will be throttled increasingly, and consequently the downward movement of the piston and of the cutter head will be progressively retarded.

Such retardation of the cutter head movement is greater if the apertures 88, 6 i, 62 and 63 are of progressively smaller size, as shownin Figure 3. Although the cutter head moves comparatively rapidly while making the firstportionof the cut, therefore, its rate of travel is vary substantially, although smoothly, decreased as the =--cutting operation progresses, depending upon-the spac- 'ing,.number and'size of, the cylinder.ports,.. so that the aperturein the veneer Sheetwill becut cleanly. I As soon asthe lower side of pistontfl has closed port fih therem-ainder oftheliquid in -.the lower end of cylinder 5-will be,tra,pped,-and #thecutter headwill be broughtto a.stop--by..en-

Yg'agement'of the lower end of piston rod with 'the bottom of the cylinder.

If the cylinder should leak so that there is not enough liquid in it to come up to port 63 by the time the lower side of the piston has descended to cover this port, the rate of travel of the piston -will not be retarded, but the lower end of piston rod 5| will engage the bottom of the cylinder to terminate downward movement of such rod and the cutter head positively, as a safety feature. iDuring normal operation, however, the rate of i'piston movement will decrease progressively, as discussed.

Preferably downward movement of the cutter head is timed automatically by regulating the :supply of air or steam to the space between the ipiston and cylinder 44. Inflow of the pressure rfiuid may be controlled by a valve 1 operated by an electric solenoid and timer it of conventional design. The operator need merely close the electric circuit to the valve actuating mechanism It, whereupon it will open the valve 5, hold it open for a predetermined length of time, and then close it. Venting of the cylinder will be controlled by the same mechanism to terminate the pressure exerted by connecting rod 45 on lever 4 so that it and the cutter head may be returned by springs 46 and 41. As the downward pressure on piston rod 5| is thus relieved spring 55 will move the piston 50 and piston rod upward. The pressure of the upper side of the piston against the liquid above it in cylinder 5 will immediately press clack valve ring 58 downward to open the axial piston ports 59. The liquid may then return from the upper end of the cylinder to its lower end both through port 64, by-pass 6 and the lower cylinder ports, and through the piston ports. The liquid in the cylinder will therefore not appreciably retard upward movement of the piston, and consequently the cutter head will be raised more rapidly than even its initial downward travel.

To enable the various ports 60, 6 I, 62', 63 and 84 to be drilled initially in the wall of cylinder 5 behind the by-pass chamber 6, and to afford .access to such ports for cleaning them periodical- .ly as may be required, the outer wall of the bypass may have several holes in it each closed by :a plug 65.

Since downward movement of piston 50 is arrrested as soon as it has closed the lower bleed port 63, such disposition of the piston must be coordinated with the desired lowest position of the cutter head for cutting defects from veneer sheets of a given thickness. downward movement of the holddown sho 3 is -limited by engagement with the veneer sheet, "whereas the cutter head 2 may continue to derscend after such engagement until movement of piston 50, and consequently of rod 4 and lever ii, :is stopped. When defects must be cut from veneer sheets thicker than that for which the machine is set, either shoe 3 must be shifted sl'ghtly to the right in Figure l, or downward movement of the cutter head must be terminated somewhat (earlier if its contact with the walls of aperture 136 is to be prevented.

If it is desired that the upper profile of the :aperture in a veneer sheet be the same size regardless of the thickness of the sheet, the lengthwise disposition of the shoe should not be altered for processing sheets of different thickness, but the stroke of cutter head 2 may be lengthened or shortened by releasing locknut 54, adjusting screw 53 appropriately, and again tightening the It will be evident that lock nut. By such adjustment the same clearance between the upwardly moving cutters 26 and the right end of aperture 36, as seen in Figure 4, is preserved. If, on the contrary, it is referred that the lower profile of the veneer sheet aperture be uniform regardless of the thickness of the sheet, the stroke of the cutter head should not be adjusted, but the lengthwise disposition of the holddown shoe would be altered to afford minimum clearance between the walls of its aperture and cutters 26 when the shoe 3 is resting on the upper surface of the veneer and the cutter head is in its lowermost position.

I claim as my invention:

1. A defect cutting machine comprising a table to support a sheet to be cut, a rotary cutter head having a plurality of blades rotatable about an axis generally parallel to said table, and supported above said table for movement from an upper position into a lower, defect-cutting position, a hold-down shoe, means interconnecting said shoe and table for relative movement between a released position in which said shoe is spaced a substantial distance above said table and a holding position in which said shoe and said table are close together for clamping therebetween a sheet on said table to be cut, said shoe having an aperture therein adapted to receive said cutter head so its blades normally move close alongside the sides of such aperture when said cutter head rotates in its defect-cutting position, said shoe being 'shiftable relative to said supporting means parallel to said table and transversely of said blade rotation axis, means automatically controlling said cutter head to terminate downward movement thereof, and means operable to secure said hold-down shoe against movement relative to said supporting means in any one of various positions adjusted transversely of the rotative axis of said cutter head, to dispose such shoe aperture with its sides close alongside the up wardly moving blades of said cutter head when in its lowermost position during the defect-cutting operation established by said automatic controlling means.

2. A defect cutting machine comprising a table to support a sheet to be cut, a rotary cutter head having a plurality of blades rotatable about an axis generally parallel to said table, and supported above said table for movement from an upper position into a lower, defect-cutting position, a hold-down shoe, means supporting said shoe for movement from an upper released position spaced a substantial distance above said table into a lower holding position adjacent to said table for engagement with a sheet on said table to be cut, said shoe having an aperture therein adapted to receive said cutter head so its blades normally move close alongside the sides of such aperture when said cutter head rotates in its defect-cutting position, means automatically controlling said cutter head to terminate downward movement thereof, means guiding said shoe for linear movement relative to said supporting means parallel to said table and transversely of the cutter rotation axis, clamping means operable to secure said hold-down shoe against movement relative to said supporting means in any one of various positions adjusted along a line generally parallel to said table and transversely of the rotative axis of said cutter head, to dispose such shoe aperture'with its sides close alongside the upwardly moving blades of said cutter head when in its lowermost position during the defect-cutting operation establishedby said automatic controlling means, and means restraining said shoe from movement relative to said supporting means transversely of such line of movement of said shoe.

3. A defect cutting machine comprising a table to support a sheet to be cut, a rotary cutter head having a plurality of blades rotatable about an axis generally parallel to said table, and supported above said table for movement from an upper position into a lower, defect-cutting position, a hold-down shoe, means supporting said shoe for movement from an upper released position spaced a substantial distance above said table into a lower holding position adjacent to said table 'for engagement with a sheeton said table to be cut, said shoe having an aperture therein adapted to receive said cutter head so its blades normally move close alongside the sides of such aperture when said cutter head rotates in its defect-cutting position, said shoe being shiitable relative to said supporting means parallel to said table and transversely of said blade rotation axis, means automatically controlling said cutter head to retard downward movement thereof progressively during the cutting operation, and means operable to secure said holddown shoe against movement relative to said supporting means in any one of various positions adjusted transversely of the rotation axis of said cutter head to dispose such shoe aperture with its sides close alongside the upwardly moving blades of said cutter head when in its lowermost position during the defect-cutting operation.

4. The defect cutting machine defined in claim 3, in which the automatic cutter head controlling means, in addition to retarding, movement of the cutter head, incorporates means operable to terminate downward movement thereof in a predetermined lowermost position established by said movement terminating means. i

5. A defect cutting machine comprising a table to support a sheet to be out, a rotary cutter head having a plurality of blades rotatable about an axis generally parallel to said table, and supported above said table for movement from an upper position into a lower, defect-cutting position, a hold-down shoe, means supporting said shoe for movement from an upper released posi- 10 tion spaced a substantial distance above said table into a lower holding position adjacent to said table for engagement with a sheet on said table to be out, said shoe having an aperture therein adapted to receive said cutter head so its blades normally move close alongside the sides of such aperture when said cutter head rotates in its defect-cutting position, said shoe being shiftable relative to said supporting means parallel to said table and transversely of said blade rotative axis, means automatically controlling said cutter head to retard downward movement thereof to a progressively greater degree as the cutting operation progresses, and further operable to terminate such downward movement thereof, adjusting means for said automatic cutter head controlling means operable to determine the elevation of said cutter head in its defectcutting position, and securing means for said hold-down shoe operable to secure said holddown shoe in any one of various positions adjusted transversely of the rotative axis of said cutter head, said two adjusting means cooperating to dispose said cutter head and said shoe at the completion of the cutting operation with the wall of the hold-down shoe aperture close alongside the upwardly moving blades of said cutter head regardless of the spacing between the downwardly moving cutter head blades and the wall of such shoe aperture.

ELMER H. JACOBSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 743,37 Bresman Nov. 3, 1903 972,479 Sondergard 1 Oct. 11, 1910 1,464,005 Kingsbury Aug. 7, 1923 1,548,773 Ziebarth Aug. 4, 1925 1,774,275 Johnson Aug. 26, 1930 1,942,414 Dumser Jan. 9, 1934 1,983,179 Maurer Dec. 4, 1934 2,071,519 Gragg Feb. 23, 1937 2,142,022 Ernst Dec. 27, 1938

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