US3807096A

US3807096A - Abrasive cutter end-profiling machine

Info

Publication number: US3807096A
Application number: US00329811A
Authority: US
Inventors: E Tackett; M Broscoff
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-02-05
Filing date: 1973-02-05
Publication date: 1974-04-30
Anticipated expiration: 1991-04-30

Abstract

An end-profiler for producing matching finger joints and the like in the ends of timbers and similar structural members, wherein a height-adjustable vise holds such a structural member at a first level for end-profiling by a special profiling cutter arrangement, following which the vice holds a second member, to be end-profiled to fit the first member at a second level offset from the first level by a predetermined amount, the predetermined amount normally equalling one-half spacing between successive convolutions in the profiling cutters; the special profiling cutters arrangement includes a carriage positioned to reciprocate across the end of a timber held in the vise for profiling, and a pair of elongated parallel-spaced counter rotating special ''''abrasive'''' profiling cutters having a plurality of zero-leadthreadlike contours with a shape in profile complementary to the finger joints to be produced, the direction of cutter rotation causing the cutters to cut into the sides of the work rather than the ends of the work, and the stroke of carriage reciprocation being pre-settable to cause each cutter to cut slightly more than halfway through the timber with the cuts merging at the center of thickness of the timber, thereby preventing splintering; a double-ended provision, together with a motor reversal provision, affords means for producing finger joint structure at one end and matching finger joint structure at the other end without resetting the adjustments.

Description

[111 3,807,096 Apr. 30, 1974 United States Patent [1 1 Tackett et al.

such a structural member at a first level for endprofiling by a special profiling cutter arrangement, fol- ABRASIVE CUTTER END-PROFILING MACHINE [76] Inventors: Edd Tackett, PO. Box 221, Bel Air,

lowing which the vice holds a second member, to be end-profiled to fit the first member at a second level offset from the first level by a predetermined amount,

Md. 21014; Mary E. Broscoff, P.O. Box 344, Alamogordo, N. Mex.

Feb. 5, 1973 [21] Appl. No.: 329,811

[22] Filed:

-spaced counter rotating special abrasive profiling cutters having a plurality of zero-lead-threadlike contours with a shape in profile complementary to the finger joints to be m0 4 w 6 "44 mm" W,c mw4 "/3 H7 W%R 4 "2 ma I c um l M C .w UhF HUN &5

[56] References Cited UNITED STATES PATENTS produced, the direction of cutter rotation causing the cutters to cut into the sides of the work rather than the ends of the work,

51/40 and the stroke of carriage recip- 51/40 rocation being pre-settable to cause each cutter to cut 51/40 UX slightly more than halfway through the timber with the 51 40 X cuts merging at the center of thickness of the timber,

thereby preventing splintering; a double-ended provisron m n mLa ru m e t fe ad k m mc SWHA 3030 3556 9999 HHHH 563 05 0 4 06 1 3506 3042 222 Primary Examiner--James L. Jones, Jr. together with a motor reversal provision, affords Attorney, Agent, or Firm-John F. McClellan, Sr. means for producing finger joint structure at one end and matching finger joint structure at the other end [57] ABSTRACT without re-setting the adjustments.

An end-profiler for producing matching finger joints and the like in the ends of timbers and similar structural members, wherein a height-adjustable vise holds 14 Claims, 12 Drawing Figures 1 ABRASIVE CUTTER END-PROFILING MACHINE This invention relates generally to woodworking and specifically to machines for producing matching profiled ends on timbers and similar structural members.

A principal object of the invention is to provide a machine capable of producing matched finger-type joints in even very fibrous and brittle woods without splintering or otherwise marring the finish, permitting prefinishing of wood if desired, before the finger joints are formed.

End-to-end joints are used for splicing in structural situations requiring long continuous lengths of timber. Examples of such timber lengths are found in roof stringers joining arches in vaulted roofs such as those used in churches, and, increasingly today, in commercial building such as restaurants, motel lobbies, and in expensive dwellings. The smoothly rounded so-called finger-type joint when well executed combines large surface-area for glueing, with retention of a maximum of the inherent strength of the wood, ease of installation, and fine appearance. In the best work, the joints are practically imperceptible. A variety of this joint is the saw-tooth joint which is sometimes used in place of the rounded finger joint.

One difficulty encountered in producing highest quality finger joints and sawtooth joints is that of generating clean, square-edged, unsplintered convolutions in the end grains of the pieces to be matched. A second difficulty is to offset the convolutions in the end of one piece so as to match precisely the convolutions in the end of the matching piece, eliminating requirement for later trueing of the joint.

In the prior art, no machine has been disclosed which, according to objects of this invention, provides for virtually splinter-proof end-profiling operation in combination with a convenient, high-production, easily adjustable, versatile, safe, economical, durable, and visually attractive end-profiler design.

In representative embodiment the invention includes a two-way-adjustable work holding vise and twin counter-rotating cutters arranged to cut work held by the vise from outside-in on opposite sides and towards the end of the work, each cutter penetrating somewhat more than halfway through the thickness of the work and then retracting, thus allowing merging of the cuts at the heart of the timber and avoiding splintering; special cutter structure is also disclosed.

The above and other objects and advantages of this invention will become more readily apparent on examination of the following description, including the drawings, in which:

FIG. 1 is an isometric view of a preferred embodiment of the invention;

FIG. 2 is a detail taken at 2-2, FIG. 1;

FIG. 3 is a section taken at 3-3, FIG. 1;

FIG. 4 is a side view of a way;

FIG. 5 is a side view of another way;

FIG. 6 details in side elevation a support portion of a clamp system;

FIG. 7 is an isometric detail, partially in section, of a further portion of a clamp system;

FIGS. 8 and 9 are cutter details in side elevation;

FIG. 10 is a fragmentary enlarged view of cutter.

structure; and

FIGS. 1 1a and 11b are isometric views of finger joint structure in a timber.

In the Figures, like reference numerals represent like parts.

FIG. 1 shows the general structure of a preferred embodiment 10 of the invention. This structure is preferably of a size suitable for working up to l2 X 12 inch size timbers of any ordinary length, and as such, is compactly supportable at table height.

The major component assemblies of the invention include three-way vise or clamp assembly 12 for adjustably levelling, tilting, and clamping work to be end profiled in a predetermined horizontal orientation, a movable carriage assembly 14 disposed in the midsection of the invention in position to reciprocate transversely across one end of work held in the clamp assembly, paired rotaty cutting tool assemblies 16 and 18 on the moving carriage assembly in parallel spacing sufficient to receive the width of work between them, fixed way assembly 20 for movably mounting the carriage assembly, a generally channel-shaped frame assembly 22 for holding the various parts in working relation and for containing material generated during the end-profiling operation, and a system 24 for controlling operation of the electrical parts of the mechanism.

In operation, a timber, or a group of boards or other material to be end-profiled, is laid in place, adjusted and clamped at an appropriate height in the horizontalmoving jaws of clamp assembly 12, with an end of the timber between the

counter-rotating tools

26 and 28. Sleeves 89, 93 equipped with respective setscrews 91, positioned on way 78 adjustably set the limits of reciprocation of carriage 14. Carriage assembly 14 is then reciprocated between the limits set, such as to cause each of the rotary cutting tools in turn to pass partway through the work, the rotations of the cutting tools being in a direction (see curved arrows) to cause the cutting tools tocut into the sides of the work instead of into the end of the work. The cutting passes of the cutting tools merge in the center of the work, leaving aclean, smooth end-profile, free of splinters. The timber is then removed by loosening the clamping assembly and retracting the timber.

The'cutting level of the next timber is altered by appropriate height-adjustment of the three-way clamp assembly 12 and the matching joint profile is then formed in the ends of the timber by the same means as the first formed joint.

Structure of the invention as further illustrated in FIG. 1 is as follows. Frame assembly 22, which is generally in the form of a channel, includes a horizontal base, having near and far

portions

30 and 32,

upstanding sides

34 and 36, and first and second spaced

second bracing frames

38 and 40. The separation between the frames provides room for carriage assembly 14 to reciprocate freely past the end of a timber cantilevered from the clamp assembly. In the preferred embodiment, the frame is substantially symmetrical about the transverse plane defined by the axes of rotation of the cutting tools, so that a set of clamps or clamp assembly can be installed on each end and, on reversal of the rotation of the cutting tools work can be introduced from the far end in the Figure.

The

sides

34 and 36 are substantially identical. Each side preferably has a relatively high midsection extending between the

transverse frames

38 and 40 which connect the sides, and which preferably tapers down in both directions to a relatively low height at the

ends

42 and 44 of the sides. This arrangement contains splinters and the like ejected by the profiling operation but allows good access at the ends for handling and visual inspection. The lower portions of the

bracing frames

38 and 40 extend below the base and support the sides near a downward arc-

like extension

46 and 48 of the sides which protects the

drive motors

50 and 52 from contact with external structures.

Longitudinally spaced

openings

54 and 56, 58 and 60 on the centerlines of the

respective base portions

30 and 32 provide room for the levelling roller-

jacks

62, 64 and 62 shown to rise and lower. The ends of axles mounting the jacks are held in journals as at 55, 57.

Transverse slots

66, 67 and 68, 69 (not shown) located respectively across the base near end, the midbody and the far end provide room for jaws of clamps at those locations to extend upward for clamping.

Openings

70, 72, 74 and 76, in the sidewalls provide for attachment for the

ways

78 and 80, which extend straight across the midbody 82 of the device.

A carriage way-support flange 84 extends across the bottom of the midbody 82 of the frame, and is bolted into the sidewalls at each end.

The carriage comprises a rectangular frame having top and bottom

transverse members

86 and 88 respectively, connected by

uprights

90 and 92, defining a rectangular aperture in the frame. A control rod 94 having a handle 95 passes through the near sidewall and is bolted at 96 to carriage upright 90. This rod allows the carriage to be reciprocated as described in profiling the ends of timbers.

Electrical on-off

switches

98 and 100 and reversing switch 102 control the

drive motors

50, 52 in counterrotating synchronism. Bar 104 which is better seen in FIG. 4, fixes one drive motor housing to the other, prevents the drive motor housings from rotating in reaction to the torque exerted and allows the motors to selfalign to a greater degree than if fixed to the carriage directly. The bar 104 is preferably bolted to the

bases

105, 106 ordinarily supplied for motor mounting.

Cranks 108 and 110 turn screws 112 and 114 which close and open the

jaws

116, 118 and 120, 122 of the 7 two clamp assemblies.

1 The roller jacks 62 and 64 pivot up and down together. in preadjustable relation when actuated by crank 124 through a mechanism to be described in reference to FIG. 6.

During operations, the central portion of the machine is preferably shielded with transparent plastic panels, 115 being shown, having hooks 111 or other suitable attachments to engage member 38, and having cutouts 119 to clear the work. These may be of inch thick methyl methacrylate or other suitable material, and a similar panel is preferably laid over the top to confine splinters.

FIG. 2, a detail taken at 2-2, FIG. 1 shows the carriage assembly 14 which is a sturdy rectangular frame to which the

cutting tools

26 and 28 are journalled at equal heights by

pillow blocks

126, 128, 130, 132, mounted on the upper and lower frame members. Drive

motors

50 and 52 connect below the lower pillow blocks through

misalignment couplings

134 and 136 respectively to the downward extensions of the

axles

138 and 140 of the cutting tools. Motor connecting bar 104 can be seen better in this view, connecting

motor bases

105 and 106.

An electric supply line 142 has a free loop 144 which flexes as the carriage is reciprocated by control rod 94 and supplies current for operation of the drive motors.

FIG. 3, a section taken at 3-3, FIG. 1 shows the way-system engagement with the carriage. Upper way 78 is round rod pivotally fixed, for self-alignment, between the sides of the frame and has a dovetail longitudinal slot 146 along the underside. The upper member 86 of the carriage has a complementary longitudinal dovetail 148 which forms a sliding fit with the slot in the upper way.

Lower way is a Y section bar adjustably mounted parallel with the upper way on carriage-way support flanges 84 by means of bolts 150 which engage slotted holes 151 in the lower way. The lower way has along it a series of rounded transverse recesses formed in the throat of the Y section, each recess 152 having a roller 154 or anti-friction bearing mounted in it on an axle 156 force-fitted in aligned

holes

158 and 160 formed in the lateral walls defining the recess. The circumferences of all rollers protrude upwardly into the slot in a uniform distance, forming together a carriage supporting roller conveyor between the arms of the Y section. The arms of the Y section prevent the square bottom 162 of the carriage from slipping off the rollers.

Assembly of the way and carriage system is made especially easy by the arrangement described. The bottom way can be raised to the proper position to take up the weight of the carriage either before or after the carriage is hung in place, since the open top slots 70 and 72 (FIG. 1) in the

side walls

34, 36 provide adjustment in both vertical and horizontal directions.

FIG. 4 is a side view of the top way detailing in partial section the installation of the top way in the

sides

34, 36 of the frame. The top way 78 is, as noted, a slotted rod. The ends 164 and 166 of the rod are reduced in diameter and threaded. Nuts and spacers 167 secure the ends of the way to he frame.

Installation of the top way and carriage is very easy. The carriage assembly 14 is first engaged in dovetail slot 146 in the top way 78 and the entire assembly is next hung in the

slots

70 and 72 in the side walls of the frame.

FIG. 5 is a face view of the bottom way 80 showing the relation of the vertical adjustment slots 151, roller recesses 152, rollers 154, roller axles 156 and of the circumferences of the rollers 154 as they protrude into the throat of the Y".

FIG. 6 is a diagrammatic detail in side elevation showing actuation of roller-

jacks

62 and 64 in the cutselector or clamping-level selector system of the three way vice assembly.

Bell cranks 168 and 170, which are identical, receive

shafts

172 and 174 in the

bores

176, 178 of the respective bell-cranks. Pins 180 or other suitable means fix the bellcranks to the shafts. The shafts are journalled at the ends as at 55, 57 (FIG. 1) in the sidewalls of the frames, or suitably held in any other conventional manner.

At least one end of each shaft extends from the frame and terminates in a lever 124 having a crank handle 182. The lever is arranged to pivot both bellcranks together on the shafts (as indicated by the dotted lines) by means of

turnbuckle rods

184 and 186 pivotally secured to bellcrank

arms

188 and 190 by

stub axles

182 and 194 respectively to which the rods are welded or otherwise secured. A turnbuckle 196 bridges a gap 198 between the free ends 200 and 202 of the turnbuckle rods and has opposite-direction threads at the ends of the turnbuckle, matching opposite-direction threads in the ends of the respective turnbuckle rods. By this means the pivotal-arc position of the bellcranks relative to each other is made adjustable. Since the bellcranks are the same in size and structure, this arrangement levels the

rollers

204 and 206 on the tops of the bellcranks when the bellcranks are adjusted in parallel, providing means of holding timbers level. Adjusting the bellcranks out-of-parallel by means of the bell-crank arrangement, provides means for holding timbers out-oflevel, as when curved or angled timbers are to be endprofiled. (Shims may be applied at the sides of a timber to make the same adjustment laterally when the clamps are tightened.)

The turnbuckle lever 124 may be adjustably secured to the framein any desired position as indicated by wing screw 208, which, as is typical of the operations of such units, can be screwed in to engage the side of the frame with the end of the screw. The first endprofile on the first matching timber is made with the timber elevated just clear of the frame. Appropriate elevation off-setting is then made by turning the lever 124, and the matching timber is end-profiled.

FIG. 7 details the clamp assembly which was briefly described in reference to FIG. 1. Acounter-threaded screw 112, having the threads extended to the middle 1 14 from each end is provided at each of the clamping locations. Each counter threaded screw terminates in a crank 108, 110. Clamping

jaws

116, 118 and 120, 122 arranged in sets, have threaded holes as at 123 at the lower ends engaging opposite-direction-threaded portions of the screws. The screws are joumalled in the frame sidewalls in conventional manner. The upper portions of the jaws protrude through the

transverse slots

66 and 68 in the frame. Timbers are clampedby cranking in one direction and are released by cranking in the opposite direction; the motion of the jaws is arranged to be symmetrical about the position of the roller-

jacks

62 and 64, which are located on the centerline of-the frame.

In an alternative arrangement, a fixed jaw can be employed on one side and a travelling jaw on the other.

FIG. 8 shows a sawtooth cutting tool configuration 26 for end profiling. The cutting tool is shaped like a series of truncated cones fixed in alternative base-tobase and top-to-top arrangement. It can be seen that to produce a complementary set of finger-like structures on the ends of two pieces of timber, the second piece must be shifted by onehalf pitch or thread of this zero-lead screw shape.

A bore 210 through the assembly receives axle 138. The axle has a screw thread at one end 212 which terminates in a reduced shaft portion 214 for engaging the pillow block 130. A second pillow block 132 engages the opposite end of the shaft adjacent a shoulder 216. Abrasive teeth 218' on the cutter may be of knurled structure, cemented-on granular structure or other suitable type, allowing a uniform cut to be made in either direction of cutter rotation.

FIG. 9 shows a second, preferred cutter configuration 26 generally like that of FIG. 8 but with the contours having a sinusoidal form in section, and being like the cutter of FIG. 8 also in having a zero-lead thread contour longitudinally, and teeth 218.

FIG. 10 shows a special abrasive tooth form for the cutters. Closely spaced laterally overlapping arrays or series of triangular sharp members 218 is raised from the surface of the cutter by punching through from the inside, by chiseling, or by other similar means, the base of each tooth remaining fixed at the cutter body and the apex and sides being raised free of the cutter body. The arrays of teeth are staggered relative to the direction of rotation. This configuration is designed to provide the cleanest cut possible, and to avoid crushing or shredding the wood at the edge of the cut, thereby providing the cleanest fit and thus the strongest in the joint, with-the most uniform glue thickness on assembly. When reversal of rotation is desired, using teeth as shown in FIG. 10, the cutting tools can be inverted and the motors reversed, or else the entire cutting tool and motor drive assemblies can be inverted. Too, reversal allows one work height to be set on one side and another work height to be set on the opposite side, allowing the finger-offset to be pre-established for all timbers of similar size.

It can be seen, in brief summary, that the invention provides for elevating the heavy timbers to correct position and fixing them there, and for reciprocating the relatively light and constant mass (as opposed to mass of various timbers) carriage assembly, but does not require elevation mechanism for the carriage. This arrangement, together with the direction of cutter rotation, made such as to tend to pull the work between the cutters, insuring cutting into the sides of the work, and

the unique, self-aligning carriage way and motor mount structure, contributes to provision of great precision in finger joint structure, and thus the best strength and appearance obtainable.

Obviously many modifications and variations of the present invention are possible in light of the above teachings. For example, the motors may be top mounted on the cutters without varying the nature of the invention. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

We claim:

1. An end-profiling machine, comprising means for holding an elongate member at adjustable height in a predetermined horizontal orientation, means for profiling finger-joint structure in an end of an elongate member held in the means for holding, including parallel spaced, counter-rotating, cutting means having vertical axes of rotation, means for reciprocating the cutting means horizontally across the end of an elongate member held in the adjustable holding means, and means for limiting amplitude of reciprocation of the cutting means.

2. An end-profiling machine as recited in claim 1, wherein the cutting means spacing is sufficient to receive the end of an elongate member therebetween, wherein the cutting means counter-rotations are in direction tending to pull an elongate member between the cutting means, and wherein the means for limiting amplitude of reciprocation is located in position to allow each cutting means on reciprocation to cut past the center-line of, but less than the full width of an elongate member held in the holding means, thereby preventing splintering during end-profiling.

3. An end-profiling machine as recited in claim 2, wherein the means for holding includes at least one clamp assembly having a pair of horizontally opening and closing jaws and at least one jack assembly located proximate the clamp for adjusting the height of an elongate member to be held in the clamp; wherein the means for reciprocating includes at least one way and a carriage on the way having journal means for holding the cutting means; and wherein a frame is provided fixing the way transversely to the direction of said predetermined horizontal orientation, in spaced relation to the clamp means.

4. An end-profiling machine as recited in claim 3, wherein a second said means for holding is provided, the first said and second said means for holding being symmetrically disposed on opposite sides of the carriage, and where means are provided for reversing the direction of rotation of the counter-rotating cutters, thereby providing for end-profiling of matching splinter-free finger joint structures sequentially on use of pre-set offset heights in the respective holding means and employing reversal of the direction of cutter rotation.

5. An end-profiling machine as recited in claim 3, wherein the jack assembly comprises a pair of pivotal roller jacks in alignment along the direction of said predetermined horizontal orientation, wherein means for pivoting one said jack is provided, and wherein an adjustable length pivotal connector is provided between the roller jacks for thereby pivoting the roller jacks together.

6. An end-profiling machine as recited in claim 3, wherein the means for reciprocating includes a pair of ways horizontally disposed in substantially upper and lower parallel-spaced relation, and wherein the carriage comprises a rectangular member having an upper edge engaging the upper way and a lower edge engaging the lower way.

7. An end-profiling machine as recited in claim 6,

wherein the upper way comprises a rod pivotally fixed for self alignment to the frame and having a dovetail longitudinal slot along the underside, and wherein the upper way has a complementary longitudinal dovetail forming a sliding fit with said slot.

8. An end-profiling machine as recited in claim 7, wherein the lower way comprises a Y section bar with a series of rollers mounted transversely along the throat of the Y section, thereby providing for antifriction engagement of the rollers with the lower edge of the carriage and for guidance of the lower edge of the carriage by the arms of the Y section.

9. An end-profiling machine as recited in claim 3, wherein a motor drive is axially attached to each cutting means and wherein a plate is provided connecting the respective motor means.

10. An end-profiling machine as recited in claim 3, wherein the cutting means comprise a pair of cutters shaped generally like a series of truncated cones fixed in alternative base-to-base and top to-top arrangement.

11. An end-profiling machine as recited in claim 10, wherein the contours of the cutters are generally of sawtooth configuration in section.

12. An end-profiling machine as recited in claim 10, wherein the contours of the cutters are generally of sinusoidal configuration in section.

13. An end-profiling machine as recited in claim 10, wherein a cutter has teeth comprising laterally overlapping arrays of triangular sharp members with the base of each sharp member fixed at the cutter body and the apex free of the cutter body.

14. An end-profiling machine as recited in claim 4, wherein the frame comprises a horizontal channel having upright sides, with the sides highest in the center and tapering down symmetrically toward each end of the frame, thereby providing working access at the ends of the frame.

Claims

7. An end-profiling machine as recited in claim 6, wherein the upper way comprises a rod pivotally fixed for self alignment to the frame and having a dovetail longitudinal slot along the underside, and wherein the upper way has a complementary longitudinal dovetail forming a sliding fit with said slot.

8. An end-profiling machine as recited in claim 7, wherein the lower way comprises a ''''Y'''' section bar with a series of rollers mounted transversely along the throat of the ''''Y'''' section, thereby providing for anti-friction engagement of the rollers with the lower edge of the carriage and for guidance of the lower edge of the carriage by the arms of the ''''Y'''' section.

10. An end-profiling machine as recited in claim 3, wherein the cutting means comprise a pair of cutters shaped generally like a series of truncated cones fixed in alternative base-to-base and top-to-top arrangement.