US2804892A

US2804892A - Work hold-down for jointers

Info

Publication number: US2804892A
Authority: US
Inventors: Russell E Peterson
Original assignee: Individual
Current assignee: Individual
Priority date: 1954-09-13
Filing date: 1954-09-13
Publication date: 1957-09-03
Anticipated expiration: 1974-09-03

Description

Sept. 3, 1957 R. E. PETERSON WORK HOLD-DOWN FOR JOINTERS 2 Sheets-Sheet 1 Filed Sept. 13, 1954 INVENTOR RusselZE. Peiersan.

Sept. 3, 1957 R. E. PETERSON 2,304,392

WORK HOLD-DOWN FUR JOINTERS Filed Sept. 15, 19,54 2 Sheets-Sheet 2 INVENTOR RussellE Peierson BY HTTYS United States Patent Ofiice 2,804,892 Patented Sept. 3, 1957 WORK HOLD-DOWN FOR J OlINTERS Russell E. Peterson, Turlock, Calif.

Application September 13, 1954, Serial No. 455,710

3 Claims. (Cl. 144-242) This invention relates to attachments to power-driven wood-working tools, particularly tools of the type known as jointers.

Considering a jointer, for which my device has been especially designed, such a tool includes front and rear tables, spaced apart, and a rotary cutter head exposed in the space between the tables. While jointers as now marketed are provided with a guard over the cutter head, this is only effective when the tool is not in use, and no Work hold-down device is provided. By reason of this arrangement, the hands must be used to both advance and press down the work over the cutter head, and since the guard is pushed aside by the work as it advances, the cutter head is exposed directly under the work and the hand holding down such work. Serious cutting of the fingers frequently results.

The principal object of my invention is to eliminate the above described dangerous feature of a jointer by the provision of a device which serves as an eflicient hold-down means for the work as it is advanced, and also forms a guard over the cutter head. The use of the hands to hold down the work as it passes over the cutter head is therefore rendered unnecessary, and the possibility of finger or hand cutting is eliminated.

The device includes work-engaging hold-down blades, and another object of the invention is to arrange and mount the blades so that constant pressure on the work, regardless of its thickness, will be exerted thereon as it passes over the cutter head, and without any adjustment on the part of the operator being necessary.

A jointer includes a fence, and another object of the invention is to so mount the device on the fence that it may be swung up out of the way when desired, as for cleaning of the tables and other parts of the jointer when the same is not in use, or for edge jointing work.

It is also an object of the invention to provide a work hold-down for jointers, which is designed for ease and economy of manufacture.

A still further object of the invention is to provide a practical, reliable, and durable work hold-down for jointers, and one which will be exceedingly effective for the purpose for which it is designed.

These objects are accomplished by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims.

In the drawings:

Fig. 1 is a front end elevation of the work hold-down device, as mounted on a conventional jointer as fragmentarily and diagrammatically shown.

Fig. 2 is a side view of the device, as in operation, partly broken away and in section.

Fig. 3 is a top plan view of the device, detached.

Referring now more particularly to the drawings, and to the characters of reference marked thereon, the improved work hold down device, as here shown, is designed for mounting on a conventional jointer which includes a front table 1, a rear table 2 spaced somewhat from table 1, a rotary cutter head 3 exposed between the tables, and a fence 4 upstanding from the tables at one side thereof.

The work hold-down devicecomprises a bar 5 which rests on top of the fence in the longitudinal zone of the adjacent separated ends of the tables, and such bar is secured to the fence by bolts 6. Upstanding from the bar 5 intermediate its ends are cars 7 serving as supports for the pivot bolts 8 of the adjacent side of a transversely extending frame 9 which overhangs the table unit of the jointer.

The frame 9 includes horizontal transverse bars 10 spaced lengthwise of the jointer, and which are integrally connected at their outer end by a bar 11. Another bar 12 connects the bars 10 above the same and intermediate their ends, and an ear 13 upstands from the bar 12 centrally between the bars 10. A yoke 14 is pivoted on the car 13 and is rigid with a rod 15 extending transversely over the bar 5 and releasably engaging in the upper end notch 16 of a boss 17 upstanding from the bar 5. The adjacent end portion of the rod 15 is threaded and is fitted with an adjustable retaining nut 18 which engages the back side of the boss, and a holding nut 19 on the front side of the boss.

By reason of this feature, the frame 9 is normally held rigid, while it may be adjusted so that the lower edge of the work-engaging members (later described) may be maintained accurately parallel to the tables of the jointer, or it may be swung up to a position well clear of the tables and cutter head, as indicated in dotted lines in Fig. 1.

Depending from the bars 10 of the frame 9 are substantially identical but independent work hold-down blades 20 which extend transversely of the tables for substantially their full width and terminate adjacent the same; one blade normally overlying the table 1 and the other blade overlying the table 2.

Alined eyes 21 are rigidly secured on each blade along its upper edge, to register with lugs 22 depending from the adjacent frame bar 10; a pivot pin 23 projecting through the lugs and eyes and pivoting the blades on the frame for swinging movement lengthwise of the jointer.

A torque spring 24, which may be of a well-known adjustable type, is disposed about each pin 23 between eyes 24, and at one end engages the corresponding blade and at the other end engages a stop 25 arranged in fixed connection with the bar 12 in such a manner as to resist rotation of the blade in the direction of the rear end of the jointer.

Unwinding of each spring, so that the same is maintained under a predetermined normal load, is prevented by means of a stop 26 formed with and depending from the related bar 12 and engaging the corresponding blade 20 adjacent its upper edge and on the front side thereof.

Each blade is rigid in itself; all yieldability being had by reason of the spring-resisted pivot mounting thereof, and each such blade is formed with a convex curvature in the direction of the forward end of the jointer; i. e., the end from which the work 27 approaches the cutter head, as shown in Fig. 2.

In operation, the hold-down blades normally hang in a depending position against the stops 26, and the cutter head 3 is shielded both from the front and back by the rigid blades whichtogether with the mounting frame 'aboveform a protecting hood over the danger zone.

When the work 27 is advanced on table 1 toward the cutter head 3, the forward end of such work engages the curved face of, and deflects, the front hold-down blade 20, causing the latter to swing rearwardly and upwardly about its pivot pin 23 as an axis, and yet always presenting a curved surface against the top of the work.

The thicker and heavier the work, the greater will be the deflection of the blade, and the more the corresponding spring 23 will be loaded, resulting in a more forceful hold-down action onthe work, as will beevident. Su-ch defiec tionof the front blade 20 places the hold-down pressure directly over the cutter'head and where most needed.

The pressure is maintained on the work as it advances onto table 2l'by engagement with, and similar deflection of, the rear hold-down blade 29. Once" the work is engaged by both hold-down blades 20, it is only necessary for the operator to impart an advancing motion to the work, and the hands need not belpresseddown on the work close to the cutterhead, as is at present required.

Thus, with my improved work hold-down and guard device, not only is the work firmlyheld down on the :tables as it moves past the cutter head, but the'danger'of accidents, caused by possible slippage'of thework and the otherwise exposed rapidly rotating cutter head, is eliminated.

The convex curvature of the blades is an important factor in the eflicient hold-down action of the blades 20, since as the thickness of the work increases and the blades are swung further up, the curved surface of the blades, rather than the lower edge thereof, engages the work. The point of engagement is thus shifted closer to the pivot pin 23 to compensate'for the :greater torsioning of the spring caused by such greater upward'swing. Also, such point remains close to a position over the cutter head.

For use when the device is installed on 'a heavyduty j'ointer having a wider fence, the mounting bar isformedginterrnediate its ends, with a laterallyproject-ing'boss "28 tapped to receive a set screw 29 to engage the wider top flange of the fence, as indicated. This set screw -gives added stability to the overhanging frame and takes some of the strain off the holding bolts 6, which must resist the'tendencyof the frame toraise as the blades are deflected and swung up.

While the device is herein described as used'in connection with a jointer, it is also adaptable to other types of wood working tools which include a rotary cutting element; as-for examplea shaper or'a circular saw.

From the foregoing description it Willbe readily seen that there has been produced such a device as-willsubstantially fulfill the objects of the inventiongas set forth herein. I 7

While this specification sets forth in detail the'present and-preferred construction of the device, still in practice such deviations therefrom maybe resortedto as do not form a departure from the spirit of the invention, as defined by the appended claims.

Having thus described the invention the following is claimed as new and useful, and upon which Letters Patent are desired:

l. A work hold-down attachment for a wood working tool'whic'h includes a' table unitand a rotary cutting member mounted intermediate the ends thereof, said attachment comprising a fixed frame disposed above and extending transversely of the table unit adjacent and above the cutter member, a spring-urged work engaging blade mounted on and depending from the frame in an initial position with its lower :edgeoverhanging the table unit adjacentthemem'ber, the tool having a-tence upstanding from one side of the table unit, mounting means for the frame comprising a bar extending along the top of the fence and secured thereon, means pivoting the frame on the barfor swinging movement about a horizontal axis lengthwise of the fence,:.and a reieasable brace connection between the frame and bar normally maintaining the frame rigid with the bar.

2. A device, as in claim 1, with means to adjust the operative length of the brace so as to act on the frame and maintainthe lower-edge of the blade parallel with the table.

3. A work hold-down attachment for a wood working moi which -inel-udesatable unit, a rotary cutting member projecting up throughthe unit from below the same, and a -fence upstanding from one side of the table unit and having aflatitop 'edge; said attachment comprising a frame above'andnormally extending transversely of the table unit adjacent the cutter member and latchable in such position, a work =engaging blade extending transversely of a-ndrnountedon an'd depending from the frame in position to engage work advancing toward the cutting member, a bar extendingalong and resting on said top edge -of the fence, means pivoting the frame on the bar for swingingmovement of the frame when unlatched about an axis parallebto =the'bar, and bol-tssecuring the bar-ion .the'fence.

References Cited inthe file'ofthis patent v 5 UNITED STATES PATENTS