US3547171A - Woodworking method - Google Patents

Description

United States Patent Jimmy R. Jacumin P.O. Box A, Icard, N.C. 28666 211 Appl. No 833,465

[72] lnventor [22] Filed June 16.1969

Division of Ser. No. 783,651, Dec. 13, 1968, Pat. No. 3,483,904.

[45] Patented Dec. 15,1970

[54] WOODWORKING METHOD 1] Claims. 20 Drawing Figs.

144/3, 144/85, 144/136, 144/326 [51] Int. Cl B271 1/00 [50] Field of Search 144/1-3,

[56] References Cited UNITED STATES PATENTS 2,593,744 4/1952 Gillespie 144/45 3.306,324 2/1967 Lillywhite 144/3 Primary Examiner-Gerald A. Dost Attorney-Parrott, Bell, Seltzer, Park and Gibson ABSTRACT: workpieces such as drawer front blanks for French dovetail style furniture drawers are formed by an apparatus and in accordance with a method in which timed, controlled, movement between a workpiece and a plurality of cutting means quickly and economically forms grooves in the workpiece as for accommodating drawer sides and a drawer bottom. Boring means are mounted on a common supporting frame with the cutting means and cooperate for forming hardware receiving holes in the workpiece in controlled timed relation to the formation of grooves therein.

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ATTORNEYS WOODWORKING METHOD This application is a divisional application of may copending application Ser. No. 783,651, filed Dec. 13, 1968, now Pat. No. 3,483,904 and entitled "Woodworking Machine and Method.

In the construction of furniture, a drawer typically includes a drawer front, drawer sides, and a drawer bottom, joined together with with mortise and tenon joints. One system of mortise and tenon joints used in assembling furniture drawers is the French dovetail style, in which the inward or rearward face of a drawer front is shaped to have a pair of parallel, spaced apart dovetail grooves extending from one edge of the drawer front vertically thereacross and adapted to receive dovetail tenons at the forward ends of the drawer sides. Extending between and transversely to the pair of dovetail grooves is a mortise which receives the forward end of the drawer bottom on assembly of the drawer.

While this system of assembling furniture drawers is recognized as being a strong and relatively simple system of construction, drawers assembled in French dovetail style have not been greatly used in recent years. This is believed principally due to the expense of producing a French dovetail style drawer front as compared with the expense of other mortise and tenon constructions. In particular, this system of furniture drawer assembly originated when cabinet work was essentially a manual operation performed by highly skilled craftsmen.

With the advent of specialized woodworking machinery, cabinet work became almost completely mechanized for increased efficiency and economic reasons. With such woodworking machinery, a repeated number of passes of a drawer front blank through a number of different woodworking machines was necessary in order to form the workpiece into a French dovetail style drawer front. Further, machinery was developed for forming another style of mortise and tenon drawer front and side joint, known as Dodds dovetail, which required fewer machines and fewer production steps. Thus, furniture production efficiency was higher with adoption of Dodds dovetail construction and the French dovetail style fell out of use.

Nevertheless, it was realized that the French dovetail drawer construction was susceptible to providing drawers of greater strength and structural integrity for given material sizes and thus would permit attaining comparable quality of drawer construction at somewhat lower material cost. These factors made the use of French dovetail style drawer assembly attractive if the manufacturing disadvantages could be overcome.

With the foregoing discussion in mind, it is an object of the present invention to form workpieces such as drawer front blanks in accordance with a method and through the use of an apparatus wherein the economic disadvantages which have heretofore made French dovetail drawer assemblies economically unattractive are avoided. In realizing this object of the invention, a method is followed and a single apparatus provided wherein the passage of a drawer front blank into engagement with a plurality of cutting means is attained by moving the workpiece and the cutting means relative to each other in controlled timed relation so that all forming of the workpiece required to accommodate assembly of the workpiece into a French dovetail style drawer is accomplished within a very short span of time and without a repeated number of passes thereof through a number of different woodworking machines.

A more specific object of the present invention is to form in a drawer front blank grooves adapted to receive the forward ends of drawer side elements and the forward end of a drawer bottom element, with the grooves being formed during a single pass of the front trough a forming apparatus and without further hand work. Apparatus for realizing this object of the present invention includes workpiece holding means and means for controlling relative movement among the workpiece holding means and forming instrumentallties including a dovetail cutting means and a bottom grooving means, all mounted upon a common supporting frame structure and wherein the movement of various ones of the apparatus elements is so controlled that a workpiece being shaped is moved along a predetermined path of travel relative to certain operating elements of the apparatus while other operating elements move relative to the workpiece.

Yet another object of the present invention is the forming of a drawer front blank in accordance with a method wherein the sequence of operations involved in forming a blank is quickly completed, so that efficient production is achieved. In realizing this object, a blank is clamped in engagement with a worktable, moves with the worktable from a first position removed from dovetail cutting means to a second position in engagement with the dovetail cutting means, and has bottom grooving means passed into engagement with the workpiece while the workpiece is maintained at the second position.

Some of the objects and advantages of the invention having been stated, others will appear as the description proceeds, when taken in connection with the accompanying drawings, in which:

FIG. 1 is perspective view of a drawer front blank as formed in accordance with the method of this invention;

FIG. 2 is a view similar to FIG. 1, showing the drawer front blank inverted from the position of FIG. I;

FIG. 3 is a perspective view of an apparatus in accordance with this invention;

FIG. 4 is a front elevation view of the apparatus of FIG. 3;

FIG. 5 is an enlarged side elevation view, in partial section, of the apparatus of FIGS. 3 and 4 taken generally as along the line 5-5 in FIG. 4;

FIG. 6 is a view similar to FIG. 5 taken generally as along the line 6-6 in FIG. 4;

FIG. 7 is a plan view, in partial section, of the apparatus of FIGS. 3 and 4;

FIG. 8 is a side elevation view, in partial section, of a portion of the apparatus shown in FIG. 6;

FIG. 9 is a plan view of the portion of the apparatus shown in FIG. 8;

FIG. 10 is a front elevation view, in partial section, of the portion of the apparatus shown in FIGS. 8 and 9;

FIG. II is an enlarged front elevation view, in partial section, of a portion of the apparatus of FIG. 4;

FIG. 12 is an exploded detail view ofa stop block portion of the apparatus of FIG. 5;

FIG. 13 is a schematic view of a portion of a control means for the apparatus of this invention;

FIG. 14 is a function sequence diagram representing the operational steps in a cycle of drawer front blank formation by the apparatus of this invention;

FIGS. 15A and 15B are schematic diagrams of fluid pressure systems used in the apparatus of this invention; and

FIGS. 16, I7, 18 and I9 are schematic showings of the relationships among a workpiece, dovetail grooving means, bottom grooving means and boring means during a function sequence in accordance with a method of this invention.

Referring now more particularly to the drawings, an apparatus in accordance with the present invention is there generally indicated by the reference character 20 (FIG. 3), and the method of the present invention will hereinafter be described with particular reference to the operation of the apparatus 20 which is provided with instrumentalities for forming an elongate wooden workpiece W (FIGS. 1 and 2) as a drawer front blank prepared for assembly into a French dovetail style drawer. These apparatus instrumentalities include dovetail cutting means for forming dovetail mortises or grooves SI and S2 in opposite end portions of the workpiece W, bottom grooving means for forming a drawer bottom mortise or groove B in the workpiece, and boring means for forming holes in the workpiece spaced in predetermined relationship to the dovetail and drawer bottom grooves. To cooperate with the workpiece forming instrumentalities, means are provided for receiving and moving a workpiece relative to certain of the operating instrumentalities while moving other of the operating instrumentalities relative to the workpiece. The

various means which shape and move the workpiece are supported on a frame structure and are actuated in a functional sequence governed by a control means.

The supporting frame structure of the apparatus includes a main frame formed by four comer standards 2I, 22, 23, 24 (FIGS. 3 and 4) which are joined together by upper and lower side members 27, 28, 29 and 30 and upper and lower front and rear members 31, 32, 33 and 34. Extending transversely of the main frame, between opposing upper side members 27 and 29, are a plurality of transverse guideways 37, 38 and 39 (FIGS. 4- -7) preferably defined by steel shaft members. Together, the various standards and members of the main frame define a structure on which the various operating instrumentalities of the apparatus 20 are mounted.

Mounted on the transverse guideways 37, 38 and 39 are a pair of side subframes 40 and 41 (FIGS. 47). One of the side 'subframes, shown as the right subframe 40, is fixed relative to 'the transverse guideways 37, 38 and 39, while the other of the side subframes, shown as the left subframe M, is movable therealong by rotation of a transverse hand screw 42 in order to accommodate workpieces of varying widths.

Each of the side subframes 40 and 41 supports a corresponding rightand left- hand portion 43, 44, respectively, of a workpiece receiving and supporting worktable. The worktable portions 43, 44 are supported on the side subframes 40, 41

for movement transverse to the guideways 37, 38, 39 along predetermined paths of travel, as discussed more fully hereinafter, and have upstanding side fences or stops 45, 46 mounted thereon for engagement with the side edges of a workpiece being formed.

To provide for formation in the workpiece W of dovetail .tnortises or grooves S1 and S2 adapted to receive mating -ten0ns formed at the forward ends of drawer sides, the apparatus 20 includes dovetail cutting means having cutter heads for forming dovetail grooves. In the illustrated embodiment, the dovetail cutting means comprises a pair of cutter driving motors 54 and 55 respectively supported on the side ' subframes 40 and 41 and arranged with the shafts of the motors disposed in a vertical orientation and terminating adjacent respective edges of the worktable portions 43, 44.

Suitable dovetail cutters or cutting heads 56, 57 are secured to .the drive shafts of respective ones of the motors 54, 55, to be driven thereby in rotation and to form dovetail mortises in the end portions of an elongate workpiece W brought into engagement therewith (FIGS. II and I7).

An operator of the apparatus 20 is protected against accidental injury by or engagement with the cutting heads 56, 57 by the provision of workpiece stops 58, 59 mounted on respective side fences 45, 46. With the worktable portions 43, 44 in a position removed from the dovetail cutting means, as

rot positioning a workpiece W on the worktable (FIGS. 3 and the workpiece stops 58, 59 shield the cutting heads 56, 57

'frbm ready engagement by an operator standing in front of the apparatus 20. Further, the stope 58, $9 additionally serve to position a workpiece placed on the worktable and as chip breakers or splitting preventors during shaping of the workpiece W, by retaining the wood fibers of a workpiece against forces arising on entry of the cutter heads thereinto and otherwise causing chipping or splitting.

Vertical adjustment of the position of the cutting heads 56, 57 relative to the worktable 43, 44 is made by rotation of the motors 54, 55 relative to motor mounting rings 60, 61. By threaded engagement of the mounting rings 60, 61 with the main frames of the motors 54, 55 and by securement of the ht'ounting rings 60, 61 to the subframes 40, 41, such relative rotation results in raising and lowering the cutting heads 56, $7mounted on the ends of shafts of the motors and permits adjusting the height of those cutting heads as may be desired or required.

'-l'I'o retain a workpiece W on the worktable 43, 44 during the forming thereof, clamping means are provided including mo'vably supported clamping members 62, 63 respectively rirounted on the side fences 45, 46 to overlie the worktable portions 43, 44 (FIGS. 3, 5 and 6). Each of the clamping members 62, 63 has a corresponding pressure fluid actuated cylinder device 64, 65 operatively connected thereto, for displacing the clamping members 62, 63 relative to the surface of the worktable 43, 44.

Relative movement of one of the workpiece W and the dovetail cutting means relative to the other, for formation of a pair of dovetail grooves in the workpiece W is obtained in the illustrated apparatus through the provision of means operatively connected with the table portions 43, 44 for displacing the same relative to the framework of the apparatus 20. As illustrated, each of the worktable portions 43, 44 has a rack member mounted thereon, shown respectively as dovetail mounting racks 66, 67. The racks cooperate with other elements to be described to assure that movement of the two worktable portions 43, 44 relative to the frame of the apparatus 20 is properly coordinated and additionally serve a mounting and guiding function by engagement with mating slots in the side subframes 40, 41. It is recognized that other means may be provided to perform the mounting and guiding functions.

Each of the racks 66 and 67 meshes with a corresponding one of two pinions 68, 69, mounted on a cross-shaft 70 for rotation therewith, to thereby insure that translational movement of the racks 66, 67 and of the corresponding worktable portions 43, 44 is properly coordinated. The cross-shaft 70 is driven in rotation by means of a driving rack 71 engaging a driven pinion 72, with the driving rack 71 being displaced by a pressure fluid actuated cylinder device 74 (FIG. 5). In order to permit adjusting the extent of movement of the worktable portions 43, 44 relative to the frame of the apparatus 20, the driving rack 71 includes provision for an adjustable stop block means 75 (FIGS. 5 and 12) to be mounted thereon and adjusted for a desired extent of movement as described hereinafter.

For forming in the workpiece W a drawer bottom groove B (FIG. 2) transverse to, extending between and intercepted by a pair of spaced apart dovetail grooves S1 and S2, and adapted to receive the forward end of a drawer bottom on assembly of the workpiece into a drawer, the apparatus 20 includes a drawer bottom grooving means. The drawer bottom grooving means in the illustrated apparatus 20 is mounted on a traversing subframe 76 (FIGS. 4, 6 and 8) which is supported on two of the transverse guideways 38, 39 for movement from side to side of the main frame of the apparatus 20. Mounted on the traversing subframe 76 is a drive motor 77 for the grooving means, having a driven shaft extending forwardly from the motor with a grooving saw 78 mounted thereon. The motor 77 is mounted on the traversing subframe 76 for pivotal movement about an axis defined by a pair of mounting bolts 79 and 80 and is moved pivotally in response to the application of fluid pressure to an actuating cylinder 81. Pivotal movement of the motor 77 moves the saw 78 on the extremity of the shaft thereof between a lowered or retracted position (FIG. 6) and a raised or working position (FIG. 8). Fore and aft adjustment of the position of the saw 78 relative to the dovetail cutting heads 56, 57 is made by rotation of a hand screw 82, which displaces a mounting plate 76A (FIGS. 8- -10) of the traversing subframe 76.

Relative movement between the workpiece W and the bottom grooving means is provided by actuation of an expan'sible chamber pressure fluid device, shown as a cable cylinder 83 (FIGS. 4 and 8). The cable cylinder 83 is mounted beneath the transverse guideways 37, 38, 39 and includes within the cylinder a movable piston member to which actuating cables 84, are connected. By connection of the actuating cables 84 and 85 to the traversing subframe 76, movement of the piston within the cylinder 83 on admission of pressure fluid thereto draws the traversing subframe 76 from side to side of the apparatus 20 and thus moves the grooving saw 78 relative to a workpiece W. Such relative movement of the bottom grooving means and workpiece forms in the workpiece a drawer bottom groove parallel to the bottom side edge of the workpiece, and transverse to a pair of spaced apart dovetail grooves cut by the cutting heads 56, 57.

For the formation in the workpiece W of holes particularly adapted to receive hardware items such as a center guide and drawer pulls, boring means are provided and incorporated in the apparatus 20. In the illustrated embodiment, the boring means includes a plurality of boring heads 87, 88, 89 and 90 (FIGS. 3, 4 and 6). Each of the boring heads includes a cor responding boring bit 91, 92, 93 and 94, each driven in rotation about a corresponding axis. The illustrated boring heads 87, 88, 89 and 90 represent a commercially available "Aro boring head which has heretofore been used in the wood working industry and thus is known to persons skilled in the manufacture and use of woodworking machinery. Boring heads of this type are pressure fluid actuated to drive boring bits mounted therein in rotation and to additionally feed the boring bits into a workpiece at a predetermined rate, to form holes therein, and return the boring bits to a retracted position on removal of fluid pressure.

One of the boring bit heads, namely the boring head 87, is mounted from the forwardmost of the transverse guideways 37, and is directed upwardly (FIG. 6) to form in the workpiece W a blind hole (FIG. 2) for receiving the forward or nose end of a drawer guide clement. While such an element is not always used with an assembled furniture drawer, the provision of this boring head 87 is a desirable feature where such hardware elements are to be employed. It is to be understood, however, that the center guide boring head 87 may be disabled by blocking admission of pressure fluid thereto or removed should its function not be required for a particular type of workpiece.

The remainder of the boring heads, namely the heads 88, 89 and 90, are mounted on a transverse carriage member 95 supported on a transverse carriage guideway 96 for movement relative to the worktable 43, 44. The mounting of the boring heads 88,89, 90 is such that the angular alignment of the axes of the bits 92, 93, 94 thereof relative to the workpiece W may be changed, where desired in order to accommodate a special hardware element, by rotating the mounting of a corresponding one of the boring heads 88, 89, 90 about an axis perpendicular to the carriage guideway 96, and generally parallel to fore and afl guideways 98, and 99 (FIGS. 3 and 4) on which the transverse carriage guideway is mounted. 0n actuation of the boring heads 88, 89, 90, the bits 92, 93, 94 thereof are driven in rotation and downwardly into the workpiece W, for the formation of holes D1, D2, D3, and D4 (FIGS. 1 and 2) particularly adapted to receive drawer pulls.

In accordance with a particular feature of the apparatus 20 of the present invention, the carriage 95 on which the boring heads 88, 89, 90 are mounted is translated laterally in order to displace the axes of rotation of the bit means 92, 93, 94 relative to the workpiece in a particular manner and thereby form pairs of holes in the workpiece w in predetermined spaced relations.

More particularly, mounting of the carriage 95 on the transverse guideway 96 and thus on the fore and aft guideways 98, 99 which are in turn supported by four superstructure standards 100, I01, 102, 103 provides the capability of displacing the axes of rotation of the bit means 92, 93, 94 in two coordinate lateral directions relative to a workpiece W secured on the worktable 43, 44. A fore and aft actuating cylinder I05 (FIGS. 3 and 5) and a side-to-side actuating cylinder 106 (FIGS. 3 and 4) are operatively connected to the carriage 95 and to the transverse guideway 96 to control movement in these two coordinate directions. Preferably, stop collars 108, 109 and 110, Ill are mounted on the guideways 96 and 98, respectively, to limit the extent of movement permitted and thereby control the spacing of a pair of openings formed by successive actuation of a single one of the boring heads 88, 89, 90. The use of the stop collars permit fore and aft or side-toside movement of any given one or more boring heads, between successive actuations thereof, by a distance less than, equal to, or more than the center line distance at which the heads are mounted when immediately adjacent one another, and thereby accommodate any hardware mounting desired.

Where the stop collars 110, 111, on the fore and aft guideway 98 are spaced to permit fore and aft movement of the carriage on admission of pressure fluid to the fore and aft cylinder 97, movement of the two extreme ends of the carriage is coordinated by a cross-shaft and link arrangement. A cross-shaft is supported for rotation relative to the rearward standards 101, 103 which support the boring head superstructure, and extends from side-to-side of the apparatus 20. At opposite ends of the cross-shalt 115 are sets of pivot links 116, I17 and 119, 120, respectively connected to the right and left sliding portions of the transverse guideway 98. By the cooperation of the pivot links and cross-shaft, fore and aft movement of the right end of the transverse guideway 98 in response to forces developed on admission of pressure fluid to the cylinder 105 results in coordinated fore and aft movement of the left end of the guideway.

In order to govern the sequence of operations performed on a workpiece W, in accordance with the present invention, a control means is provided for governing the actuation of the various operating instrumentalities of the apparatus 20, including the clamping means, the moving means for the worktable, the moving means for the bottom grooving means, the boring means and the moving means for the boring means. The particular interaction of the control means with the various operating instrumentalities of the apparatus 20 is herein described with reference to a schematic diagram of a portion of the control means and to a function sequence diagram as set forth in FIGS. 13 and 14. As there shown, a sequence timing motor 121 (FIG. 13) drives in rotation a cam shaft I22 on which a plurality of control cams 124 are mounted. Each control cam 124 cooperates with an associated electrical switching device 125 to control the flow of electrical current in a corresponding control circuit. Pressure fluid is delivered to the various actuated cylinders 64, 65, 74, 81, 83, 105 and 106 and to the boring heads 87, 88, 89, 90 under the control of a plurality of pressure fluid valve devices (FIGS. [5A and [513), including solenoid actuated hydraulic valves 126, 127,128 and 129 and air valves I30, 131, and 132. Each of the valves is actuated to control the admission of a suitable pressure fluid from an appropriate source of fluid under pressure in response to the energization of control circuits including solenoid coils forming a portion of each valve and identified by the addition of the reference characters a and b to the principal reference character for the valve.

The sequence of energization of the various electrical elements of the control means for the apparatus 20 is to be understood from the function sequence diagram of FIG. 14, and will become more clear from a study of that diagram in conjunction with a discussion of the operation of the apparatus which follows hereinafler. At this point, it is appropriate to note that the interconnection of the solenoid operated valves with a sequence timing means or the provision of other details required to perform the functional sequence of this invention is within the competence of a skilled electrician or other persons familiar with automatic workpiece shaping machines. Further, it is to be noted that the particular order of the functional sequence of the movements made in carrying out such a sequence may be varied within the scope of this invention, as the discussion given herein is intended as a broad teaching.

ln setting up the apparatus 20 for a production run, the sideto-side distance between the right and left side frames 40, 41 is first adjusted to accommodate the width of the workpiece W to be shaped, by rotating the transverse hand screw 42 to move the left subframe 4! relative to the right subframe 40. With the worktable portions 43, 44 thus spaced at the proper side-to-side distance to accommodate the workpiece W, the location and length of the dovetail grooves to be formed therein are determined by adjusting the positions of the fences 45, 46 on the worktable portions and the position of the stop means 75 on the driving rack 71. The fence positions determine the spacing of the dovetail mortises in the opposite end portions of the workpiece, particularly as to spacing inwardly from the side edges of the workpiece W, while the stop means 75 determines the extent of movement of the worktable 43, 44 relative to the cutting heads 56, 57 of the dovetail cutting means and thus the length of the dovetail grooves.

In the illustrated embodiment, the construction of the stop means 75 includes a pair of blocks 75A and 758 which, by virtue of a stair-steplike mating engagement, permit very accu rate determination of the extent of relative movement to be permitted, thus assuring whatever degree of accuracy is desired by the operator setting up the apparatus. The relative position of the bottom grooving saw 78 to the workpiece W is then adjusted by means of the fore and aft hand screw 82, to space the bottom receiving groove at a desired distance forwardly (or upwardly) from the rearmost (bottom) side edge of the workpiece. Finally, the stop collars 108, 109, 110, 111 for the boring head displacing means are set to determine the position of the hardware accommodating holes to be formed in the workpiece W and appropriate cutoff valves are closed to limit the admission of pressure fluid to only those actuating cylinders and boring heads required for the particular sequence of operations to be carried out or those instrumentalities are otherwise disabled as be being removed or raised.

Then, in operation of the apparatus of the present invention, an operator places a workpiece W onto the worktable 43, 44 against the workpiece stops 58, 59 and actuates a start switch to cause a cycle of the timer motor 121. Upon actuation of the timer motor 121, fluid pressure is applied to the actuating cylinders 64, 65 for the clamping means, bringing the ,clamping members 62, 63 downwardly into engagement with the workpiece W and temporarily securing the workpiece to the worktable 43, 44. Thereafter, pressure fluid is applied to the center guide boring head 87, to cause the bit 91 thereof to be driven in rotation and upwardly into the workpiece W to form a blind hole G therein (FIG. 16). Pressure is then applied to the actuating cylinder 74 for the moving means for the worktable, causing the cylinder to draw the driving rack 71 toward the rearward side of the apparatus 20 and, by means of .the cross-shaft 70 and pinions 68, 69 engaging the racks 66, 67

on the worktable portions 43, 44, causing relative movement between the worktable and the dovetail cutting means (FIG. 17). This relative movement draws the workpiece W into engagement with the cutting heads 56, 57 of the dovetail cutting means, while the cutting heads 56, 57 are driven in rotation by the motors 54, 55 to form in the end portions of the workpiece W a pair of spaced apart, parallel, dovetail grooves S1 and S2 extending across the end portions adjacent the side edges of the workpiece. With movement of the workpiece W into engagement with the dovetail cutting means, formation of the dovetail grooves proceeds from a bottom edge of the workpiece and continues until the stop means 75 on the driving rack 71 is engaged and movement of the worktable 43, 44 relative to the dovetail cutting means is stopped.

On movement of the worktable 43, 44 and the workpiece W secured thereto from the first position remote from the dovetail cutting means (FIG. 16) to the second position wherein the cutting heads 56, 57 have formed dovetail grooves in the workpiece W, (FIG. 17), pressure fluid is applied to the pivoting control cylinder 81 to pivot the motor 77 of the bottom grooving means and bring the saw 78 upwardly from beneath the workpiece W into engagement therewith. The relative position of the traverse subframe 76 to the dovetail cutting means and the diameter of the grooving saw 78 are so chosen that the saw 78 enters the workpiece at one of the two dovetail grooves formed by the dovetail cutting i'n'eans (FIG. 17). The configuration of the grooving saw 79 in the illustrated embodiment is such as to form a straight-sided mortise, rather than a dovetail mortise.

Thereafter, fluid pressure is applied to the cable cylinder 83,, to exert force on one of the cables 84, 85 and draw the traversing subframe 76 transversely of the main frame 20 (FIG. 18). Such movement of the traversing subframe 76 results in relative movement of the workpiece W and the bottom grooving means, forming in the workpiece W a bottom groove B extending transverse to and intercepted between the pair of elongate dovetail grooves.

On completion of traversal of the distance between the side subframes 40, 41 by the traversing subframe 76, the subframe engages that one of two limit switches 138, 139 which is mounted on the one of the side subframes 40, 41 toward which the traversing subframes 76 is moving and the application of pressure to the pivoting cylinder 81 is released to drop the saw 78 downwardly from the workpiece W,

While formation of the bottom groove in the workpiece W is proceeding, pressure fluid is applied to the downwardly acting boring heads 88, 89, of the boring means, to result in the bit means 92, 93, 94 being driven in rotation and being extended into engagement with the workpiece w for drilling hardware receiving holes therein (FIG. 1B). The time required for traversal of the workpiece W by the bottom grooving saw 78 is adequate to permit the formation of a first hole by a particular bit, such as the bit 92, followed by withdrawal of the bit 92, displacement of the mounting carriage 95 to translate the axis of the bit 92 from a first location to a second location, and subsequent extension of the bit 92 to form a second hole at a predetermined spaced distance from the first hole. Thus, during the time that pressure is being applied to traverse the saw 78 across the workpiece, pressure is also applied to the boring head displacing cylinders and 106 to shift the carriage 95 and is reapplied to the boring heads 88, 89, 90 to form a second hole. This operation may, of course, be omitted if unnecessary for a particular workpiece.

On conclusion of boring and bottom groove forming, and with retraction of the bottom grooving saw 78 and of the boring bits 92, 93, 94, the application of pressure fluid to the table moving cylinder 74 is reversed, driving the driving rack 71 and the table portions 43, 44 to retract the workpiece from the second position in engagement with the dovetail cutting means to the first position remote therefrom (FIG. 19). Pressure is then released from the clamping means cylinders 64, 65 to permit the workpiece W to be removed from the table portions 43, 44 and a new workpiece to be positioned thereon for shaping.

Practical experience with an apparatus as herein described has shown that the cycle of operation for a typical drawer front is sufficiently short to accommodate a production of nine or ten drawer fronts per minute. In achieving this production, it may from time to time be necessary to accommodate the particular direction of rotation of the cutting heads 56,57 of the dovetail cutting means and of the saw 78 of the bottom grooving means to the splitting characteristics of the wood being used. In particular, the apparatus 20 may normally be operated with the traversing subframe 76 moving first from right to left and, on the next subsequent operation, returning from left to right. With certain types of wood, it will be found preferable to always traverse the bottom grooving saw 78 in the same direction in order to control splitting. While this requirement may be found to somewhat delay the cycle of operation in the apparatus, it is believed apparent that the control means therefor may be so modified as to return the traversing subframe 76 with the saw 78 in the lowered or retracted position.

In the operation of the control means for the apparatus 20, it is contemplated that a time interval between initiation of traversal of the bottom grooving saw 78 of a workpiece W and retraction thereof by the reversal of pressure applied to the pivot controlling cylinder 81, will be controlled by one of the cams 124 and switches 125 driven by thetimer motor 121. However, in order to accommodate a varying width of drawer fronts being produced, the limit switches 138, 139 are employed to override this control feature under certain circumstances. In particular, the timed operation achieved from the timer motor 121 and cam shaft 122 is established to be properly coordinated with a median width of workpieces to be accommodated by the apparatus 20. Then, continuing energization of the timer motor 121 is interrupted by a cam and switch during the cycle of operation and reenegization of the timer motor is placed under the control of the limit switches 138, 139 so that the timer motor 121 cannot require that the grooving saw 78 be retracted before traversal of the workpiece W has been completed. Thus, movement of the workpiece W from the second position relative to the dovetail cutting means back to the first position may be delayed until such time as traversal of the workpiece by the bottom grooving saw 78 has been completed, as indicated by a broken segment of the bar function diagram of FIG. 14.

In the drawings and specification, there has been set forth a preferred embodiment of the invention, and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation I claim:

1. A method of forming elongate workpieces into drawer front blanks in preparation for assembly thereof with drawer sides and bottoms comprising the steps of:

clampingly supporting a workpiece on a worktable while moving dovetail cutting means and the clamped workpiece one relative to the other along a predetermined path of travel and forming in the workpiece a pair of spaced apart dovetail grooves parallel to and adjacent opposite ends of the workpiece and adapted to receive the forward ends of drawer sides on assembly thereof into a drawer; and

moving bottom grooving means and the clamped workpiece one relative to the other along a predetermined path of travel and forming in the workpiece a drawer bottom groove parallel to and adjacent the bottom edge of the workpiece and adapted to receive the forward end of a drawer bottom on assembly thereof into a drawer.

2. A method according to claim 1 wherein movement of the dovetail cutting means and the workpiece proceeds prior to movement of the bottom grooving means and the workpiece and further wherein formation of a drawer bottom groove includes forming the drawer bottom groove transverse to and extending between the dovetail grooves.

3. A method according to claim 1 further comprising the step of moving boring means and the clamp workpiece one relative to the other along a predetermined path of travel and forming in the workpiece at least one hole adapted to receive a hardware item on assembly of the workpiece into a drawer 4. A method according to claim 3 wherein movement of the boring means and the workpiece one relative to the other proceeds simultaneously with movement of the bottom grooving means and the workpiece one relative to the other.

5. A method according to claim 1 wherein movement of the dovetail cutting means and the workpiece one relative to the other includes guiding the workpiece in a predetermined path from a first position removed from the dovetail cutting means into engagement with the dovetail cutting means and to a second position spaced from the first position while the dovetail grooves are being formed.

6. A method according to claim 5 wherein movement of bottom grooving means and the workpiece one relative to the other includes traversing the bottom grooving means across the workpiece while maintaining the workpiece in said second position.

7. A method of forming workpieces into drawer front blanks in preparation for assembly thereof with drawer sides and bottoms into French dovetail drawers and comprising the steps of:

clamping a workpiece against a worktable; then moving the worktable and workpiece relative to dovetail cutting means along a predetermined path of travel and fomiing in the workpiece at least one elongate dovetail groove extending from an edge a predetermined distance across the workpiece; and then moving bottom grooving means relative to the worktable and the workpiece and forming in the workpiece an elongate groove transverse to and intersecting with the dovetail groove. 8. A method according to claim 7 further comprising moving boring bit means relative to the workpiece and the workta ble and forming in the workpiece at least one hole adapted to receive a hardware item on assembly of the workpiece into a drawer.

9. A method according to claim 8 wherein movement of boring bit means proceeds during movement of boring bit means proceeds during movement of bottom grooving means and further wherein said movement of boring bit means includes forming a first hole in the workpiece and thereafter displacing the boring bit means relative to the workpiece and forming a second hole in the workpiece in predetermined spaced relation to the first hole.

10. A method of forming elongate workpices into drawer front blanks in preparation for assembly thereof with drawer sides and bottoms comprising the steps of:

moving dovetail cutting means and a workpiece from a first position one relative to the other along a predetermined path of travel to a second position while forming in the workpiece a pair of spaced apart dovetail grooves adapted to receive the forward ends of drawer sides on as sembly of the workpiece into a drawer, and while maintaining the workpiece in the second position; and moving bottom grooving means and the workpiece one relative to the other along a predetermined path of travel and forming in the workpiece a drawer bottom groove transverse to and extending between said dovetail grooves and adapted to receive the forward end of a drawer bottom on assembly of the workpiece into a drawer. 11. A method of forming workpieces into drawer front blanks in preparation for assembly thereof with drawer sides, drawer bottoms and drawer hardware comprising the steps of:

clampingly supporting a workpiece on a worktable while moving dovetail cutting means and the workpiece one relative to the other along a predetermined path of travel and forming in opposite end portions of the workpiece dovetail mortises adapted to receive mating tenons on the forward ends of drawer sides on assembly into a drawer;

moving bottom grooving means and the workpiece one relative to the other along a predetermined path of travel and forming in the workpiece a drawer bottom groove parallel to and adjacent the bottom edge of the workpiece and adapted to receive the forward end of a drawer bottom on assembly into a drawer; and

moving boring means and the workpiece one relative to the other along a predetermined path of travel and forming in the workpiece at least one hole adapted to receive a hardware item on assembly into a drawer.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,547, 171 Dated December 15, 1970 Inventor R Jacumin It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1 line 1 "may" should be --my--;

line 8 "with" should be deleted; line 69 "trough" should be --through--.

Column 2 line 21 insert "a" between "is perspective" Column 3 line 55 "stope" should be --stops--. Column 5 line 10 insert "predetermined" between "corresponding axis" line 54 "w" should be -W-- Column 7 line 23 "be" should be -by-. Column 8 line 15 "w" should be --W-- line 60 one should be deleted. Column 10 lines 19 and 20 delete "of boring bit means proceeds during movement" line 26 "workpices" should be --workpieces Signed and sealed this 8th day of June 1971.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, JR. Attesting Officer Commissioner d Patents FORM PO-IOSO (10-69) USCOMM DC Bowed-=59 a uIsI sovuumzm' "name orncs: Ill! o-su-su

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