US872889A - Guard for rotary knives. - Google Patents

Description

- No. 872,889. PATENTED DEC. s; 1907.

- B. E. BEGHTEL & J. BALL.

GUARD FOR ROTARY KNIVES. APPLIoATIoN FILED nn0.11,19os,

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No. 872,889. PATENTED DEC. 3, 1907. B. B. BEGH-TEL & J. VBALL. GUARD FOR ROTARY KNIVES.

APPLIOATION TILED DEO.11,1906.

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THE NORRIS PETERS co., WASHINGTON, n. c.

UNITED STATES PATENT OFFICE.

BYRON EBB BEOHTEL AND JACOB BALL, OF WATERLOO, ONTARIO, CANADA.

GUARD FOR ROTARY'KNIVES.

Specification of Letters Patent.

Patented Dec. 3, 1907.

Application filed December 11. 1906. Serial No. 347.358.

To all whom it may concern:

Be it known that we, BYRON ERB BECHTEL and JACOB BALL, subjects of the King of Great Britain, residing at Waterloo, Province of Ontario, Dominion of Canada, have invented certain new and useful Improvements in Guards for Rotary Knives and the Like; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

I This invention relates to certain improvements in guards for rotary cutter heads; and more particularly relates to guards for rotary planer knives, and the like; and the objects and natureof our invention will be readily understood by those skilled in the art in the light of the following explanation of the construction shown in the accompanying drawings as the preferred embodiment from among other forms and arrangements within the spirit and scope of our invention.

An object of the invention is to provide an improved guard for rotary cutter heads which shall be quick in action with a minimum essential range of movement, and wherein a series of guard fingers will be employed which can be arranged closely together to attain the maximum guarding efficiency without necessitating weakening of the planer bed plate or table to form slots for the reception of said fingers.

A further object of the invention is to provide a guard for rotary planer knives or heads wherein a series of parallel closely arranged curved pivoted fingers is employed, each finger approximately in the form of a semicircle and arranged almost concentric with the axis of rotation of the planer or cutter head, and swinging on an axis arranged parallel with and closely below the cutter head axis, whereby the fingers can be applied without weakening the planer bed plate or table and have a short range of movement in uncovering and covering the planer knives or cutter head.

A further object of the invention is to provide an improved rotary cutter head guard comprising a series of curved parallel swinging fingers carried by and pivotally joined to the casting connecting the cutter head journal boxes.

A further object of the invention is to provide an improved rotary cutter head guard employing a series of swinging curved parallel fingers normally and yieldingly held over and guarding the cutter head and bridging the opening therefor in the planer bed plate or table, whereby the piece of wood advancing to the cutter head will engage the freeends of the guards and cause withdrawal thereof below the top surface of said bed plate; and to provide means whereby the force or power impelling said fingers to return to guarding position can be varied or reduced to ml, and whereby when said force is reduced to nil, said fingers will by gravity drop to uncover'the cutter head.

A further object of the invention is to provide certain improvements in details of con struction and arrangements whereby a highly eflicient and comparatively simple and durable rotary cutter head guard Will be produced.

The invention consists in certain novel features in construction and arrangements and combinations of parts as more fully and particularly set forth and pointed out hereinafter.

Referring to the accompanying drawings:Figure 1, is a side elevation showing portions of the frame, bed plate, cutter head, and guard of a planing machine, dotted lines indicating certain hidden parts. Fig. 2, is a detail longitudinal section, on an enlarged scale, of the bar or frame carrying the cutter head shaft journal boxes, and the guard fingers. Fig. 3, is a detail cross section through the cutter head, guard and bed. Fig. 4, is a top plan of a portion of the planer bed, showing the guard in normal position, dotted lines indicating certain hidden parts.

In the drawings, 1, is the bed plate or table of a planing machine, or the like, car ried by the frame or uprights 2, and having the transverse opening 3, in which the blades or knives 41, of the rotary cutter or planer head 5, operate and through which they project to engage the work on the bed plate.

In the specific example illustrated, the planer knives'are arranged longitudinally of and secured in any approved manner to the head or stock 5, carried by the horizontal shaft 6, rotated in any suitable manner and arranged transversely of the bed plate and below the opening or slot 3. The shaft 6, is, at its ends, mounted in usually separable journal boxes 7, carried by the frame sides or uprights 2, and the lower halves or sections of the two journal boxes are usually at the ends of a single casting or said lower journal,

box sections are rigidly connected by an elongated casting, metal bar or frame 8, arranged beneath and parallel with the planer head. This casting or bar 8, arranged longitudinally of and beneath the planer head, is spaced such a distance from the planer head that the planer knives will move above the top face of the bar with ample clearance, yet the bar is preferably arranged as close to the planer head as possible. The bar 8, is usually concavo-convex or crescent shaped in cross section with the transversely convexed bottom face. The bar is formed with a lon- 'gitudinal series of alined perforated ears 9, arranged at the under face thereof about in the vertical plane of the axis of the planer head. The lower perforated ends of the spaced parallel curved guard fingers 10, overlap these ears 9, and the fingers are supported and pivotally joined to said ears by the horizontal transverse pivot bolt or rod 11, extending through the ears and finger ends and forming the axis on which the fingers can independently swing.

Each finger 10, is usually crescent shaped or about semi-circular in form and if so desired, can taper in thickness from its lower and pivoted end to the upper and free end, and said fingers are usually similar and closely arranged to form a series in length approximately equal to the length of the plan-er knives. We usually space the guard fingers about an eighth or quarter of an inch apart, more or less, to prevent the operators fingers passing between the guard fingers into the path of the planer knives. Each finger, from its pivotal point, curves rearwardly and upwardly along the convexed lower face of the bar 8, and from thence curves upwardly in rear ofthe planer head and forwardly across the beveled edge of the bed plate forming the rear wall of the slot or opening 3, and forwardly across said slot, with its free front end dropping on or arranged above the face of' the bed plate just in advance of the opening 3. The fingers above the rear top edge of the bar 8 approximately follow the curvature of the circular path of movement of the planer knives, but with a curvature of a greater radius than that of said circular path, so that the fingers are arranged outside ofsaid circular path and hence out of contact with said knives.

If so desired, separating or spacing fins or flanges 12, can be provided between the fingers, and projecting rearwardly from the beveled bed plate edge forming the front wall of the opening or slot 3.

As so far described, the fingers would by gravity passrearwardly from the opening 3, and drop below the bed plate, and hence it is necessary to provide means to yieldingly and normally hold the fingers in their elevated operative guarding position bridging the opening 3, and closing the same over the planer head. As an example of means which can be conveniently and efficiently employed for this purpose, 'I show the lower end of each finger, in advance of the axis on which it swings, formed or provided with a rigid depending arm 13, connected by a coiled spring 14, with an arm or pin 15, rigid with and projecting up from a transverse rock shaft 16, mounted in the frame sides or uprights and rigid with a rearwardly extending lever or handle 17. Each guard finger has a separate expansion spring connection 14, with the rock shaft 16, either through a pin or crank arm 15, one for each spring, or else all the springs 14, can be connected to a uni versal bar 18, secured to and parallel with the rock shaft by a pair of the arms or pins 15, rigid with the universal bar and shaft. It is obvious, that when the shaft 16, is rocked to distend the springs 14 that the guard fingers will be thereby forced and held to their limits of upward movement in guarding position with their upper ends projecting over the bed plate in advance of the planer head.

In the specific arrangement shown, the hand lever 17, extends to an accessible point on the planing machine, and the spring tension is applied to the guard fingers to yieldingly hold them in guarding position by swinging said lever downwardly and catching the same under a holding or locking pin or catch 19, a vertical series of such pins 19, being usually arranged on the side of the frame so as to hold the lever in various positions to apply greater or less tension to the guard fingers, or to hold the lever in an elevated position with the springs 14, in con tracted or inactive position. lever is thus elevated, so that the guard finers are relieved of the spring tension, said ngers will by gravity, drop back below the bed plate and thus expose the slot 3, and the planer head to permit access to the planer head for adjustment of the knives, or for other purposes. The guards can then be quickly and easily restored to guarding position, by simply depressing the-lever and, locking the same at the position where the springs will be distended to apply the desired tension to the fingers to cause the desired quick return thereof, on being pressed back and released. In operation, the piece of wood to be planed is moved toward the bed plate toward the planing head and engages the front free ends of all or certain of the guard fingers and forces the fingers back to expose the Wood to the action of the planer knives. When the piece of wood passes rearwardly beyond the points or ends of the fingers depressed, said fingers very quickly fly back to guarding position.

By reason of the formation of the fingers and the manner of mounting the same, and also by reason of the springs employed, the fingers move a minimum distance to uncover When the i the planing head and consequently have but I circular a short return stroke to again cover said head and are very quick in action reducing to the minimum liability of accidental engagement of the planing knives with the hands or fingers of the operators.

It is evident that various changes and .modifications might be resorted to in the forms, constructions and arrangements of the parts described without departing from the spirit and scope of this invention, hence we do not wish to limit ourselves to the exact construction shown.

What we claim and desire to secure by Letters Patent is 1. In combination, a bed having a cutter head opening, a rotary cutter head operating through said opening, a bar arranged longitudinally beneath and carrying said cutter head, said bar beneath the head being transversely convexed at its ries of swinging parallel crescent shaped guard fingers carried by said bar and at their lower ends pivoted on a common axial line at the under side of said bar, said fingers adapted to extend forwardly and upwardly along said convexed surface of said bar and upwardly therefrom through and bridging said opening, said convexed surface limiting the upward swing of said fingers, said fingers normally tending by gravity to swing down from said opening, and a manually controlled spring device-yieldingly holding said fingers in operative position up against said convex surface and bridging said opening.

2. In combination, a bed having a cutter head opening, a rotary cutter head working through said opening, a removable cutter head carrying bar arranged longitudinally of and below said cutter head and provided with the cutter head journal boxes, and a guard for said cutter head comprising swinging fingers pivoted to and carried by said bar and extending upwardly therefrom and adapted to bridge said opening, and means normally and yieldingly holding said fingers in operative position bridging said opening.

3. In combination, a bed having a cutter head opening, a rotary cutter head arranged below said bed and adapted to work through said opening, a movable cutter head carrying bar arranged longitudinally of and closely below said head and provided with and carrying end journal boxes for the cutter head axis, and a cutter head guard comprising a series of swinging spring held crescent shaped fingers carried by said bar and at their lower ends arranged at the under side of the bar and pivotally joined thereto to swing on a common axial line.

4:. A rotary cutter head guard comprising a support arranged closely below and longitudinally of the cutter head, a series of closely arranged crescent shaped swinging guard fingers extending partially around the under surface, a sepath of movement of said head, said fingers at their lower ends pivotally joined to said support to swing on a common axis, whereby said fingers tend under gravity to swing down from operative position, a spring tension device applied to each finger to yieldingly hold the same up to operative position, and manually controlled means for simultaneously varying or relieving the tension of said device on'said fingers, whereby when said tension is relieved said fingers automatically drop from operative position.

5. A rotary cutter head guard comprising a series of movable guard fingers adapted to extend partially around the path of movement of said head, each finger having a retractive coiled tension spring connected thereto, and manually controlled means for simultaneously varying the tension of all of said springs, and of relieving all of said fingers from the tension of said springs to permit said fingers to drop by gravity from guarding position. 6. A rotary cutter head guard comprising a series of swinging guard fingers adapted to extend partially around said cutter head and normally tending to drop by'gravity from operative position when released from the spring pressure, each finger having a lateral arm, a rocking member, means for rocking said member and for holding the same in different positions, and retractive tension springs between said member and said arms and yieldingly holding the fingers up to operative position when said member is held in certain positions, and to relieve said fingers of the spring tension when said member is held in other positions.

7. In combination, a bed plate having an opening therethrough, arotary cutter head working through said opening, journal boxes for the axis of said head, a movable cross bar between and rigidly connecting said journal boxes, a series of swinging curved spring impelled guard fingers projecting beneath and pivoted to said bar and adapted to extend up therefrom to bridge said opening and cover said head.

8. In combination, a bed having an opening, a rotary cutter head working through said opening, a removable bar arranged longitudinally of and beneath said head and at its ends provided with the journal boxes for said head,'and a series of spring impelled curved swinging guard fingers extending beneath and engaging the under face of said bar and pivotally joined thereto and adapted to extend upwardly therefrom to bridge said opening and cover said head.

9. In combination, a bed having an opening, a rotary cutter head working through said opening, a bar arranged longitudinally of and beneath said head and formed with a series of alined ears, a series of swinging guard fingers pivotally joined to said ears different positions to vary or relieve the tension of said springs on said fingers.

a bed 10. In combination, side frames, having a cutter head opening, a rotary cutter head arranged transversely of the bed and frames and having end journals, a cutterheadcarrying movable cross bar arranged beneath said cutter head and carried by said side frames, said journals being mounted on the ends of said bar, a vertically movable cutter head guard mounted on and carried by said bar and adapted to extend yieldingly up therefrom to bridge said opening and cover said head, and means yieldingly holding said guard in operative guarding position substantially as described.

v11. In combination, a bed having a cutter head opening, a rotary cutter head rotatable through and across said opening, a cross bar arranged longitudinally of and closely below said head, a vertically swinging crescent shaped cutter head guard extending transversely of the under side of said bar and at its lower end pivotally joined to said bar at a point intermediate the width of said bar, said erases bar having a portion to one side of said pivoted end of said guard forming a stop adapted to engage said guard and limit the upward swing thereof, said guard adapted to extend upwardly from said bar to bridge said opening and cover said head, and a spring device normally yieldingly holding said guard in operative guarding position.

12. In combination, a rotary cutter head, a support arranged longitudinally thereof and adjacent thereto, a crescent shaped cutter head guard at its lower end swingingon said support and carried thereby, said guard adapted to partially surround the path of movement of said head to guard the same, said head adjacent to its lower end having a depending arm, a retractive spring attached to said arm to yieldingly hold the guard to operative position, and a movable support connected to the opposite end of said spring, whereby the tension of the spring on the guard can be varied, or can be relieved to permit the guard to drop from operative position.

In testimony whereof we aifix our signae tures in presence of two witnesses.

BYRON ERB BECHTEL. JACOB BALL. IVitnesses:

A. L. KUMPF, E. P. FLINTOFT.

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