US1807561A - Cutter guard - Google Patents

Description

A. WHITE CUTTER GUARD May 26, 1931.

3 Sheets-Sheet 1 Filed Aug. 29, 1929 /Nl EN 70R. WWLZ: 5r

ATTORNEY A. WHITE CUTTER GUARD May 26, 1931.

a QM T 0 N W 4 w 5 W 1 M l; I. W .un lmflh idmw W W F Y B 3 2 1- Eu W 7 m QR P 1/ w 2 3 5 f 4 a q. 3 a 1 w 2 GD MWM 9 or fl \M |||||liuuhnhunuufl nnn hufiumullfi I: HAW. 2 3 o I 2 W A 6 2 1 a i 3 N 0 m r ATTORNEY A. WHITE CUTTER GUARD May 26 Filed Aug. 29, 1929 3 Sheets-Sheet 5 //V VENTORI ATTORNEY Patented May 26, 1931 UNETED STATES PATENT OFFHCE ALPHONZO WHITE, or wmonnnbon, M

ASSACHU'SETTS, ASSIGNOR TO BAXTER D.

WHITNEY & 8011, INC., 0F WINCHENDON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS CUTTER GUARD Application filed August 29, 1929. Serial No. 389,223.

This invention relates to movable guards for cutters, and more particularly to guards for protecting the rotating cutters of shapers.

Shapers having a work supporting table and a vertical power-driven spindle to which a cutter is secured are extensively used in the wood workin industries. These cutters are driven at high speed usually in excess of 5000 revolutions per minute so that if a cutter breaks or works loose from the spindle it will be thrown outwardly by centrifugal force with the speed of a bullet, thus endangering the workmen near the machine.

As long as the work is in contact with the cutter, or is in close proximity thereto, the work itself will protect the machine attendant to a degree from the flying parts, in case the cutter breaks, but he is not aiforded this protection from flying parts when the work is Withdrawn.

The present invention therefore relates to a cutter guard mounted for movement to and from the cutter enclosing position, and

in mechanism for automatically shifting the guard. A

It has been proposed heretofore to employ a solenoid to move the cutter guard away from the cutter as the work is presented to the cutter, but the guard which is relatively heavy should be quickly removed from the cutter asthe work is presented to the cutter. This requiring the use of a large powerful solenoid which is expensive to manufacture.

An important feature of the present invention therefore resides in a cutter guard provided with fluid operated means for automatically shifting the guard as the Work is presented to or removed from the cutter, and a more specific feature of the invention resides in means operable by compressed air for quickly withdrawing the cutter guard as the work is presented to the cutter and for holding the guard in its retracted position until the Work is removed from the cutter.

A further-feature of'the invention resides in a cylinder into which air is introduced under pressure to move a piston in a direction to withdraw the guard, and in adjustable means for varying the speed at which the air enters V or leaves the cylinder to thereby vary the speed at which the cutter guard is shifted.

Still a further feature of the invention resides in valve operating means located near the cutter and passage of the work to and from the cutter.

Other features of the invention and novel combination of parts in addition to the above will be hereinafter described in connection with the accompanying drawings Which illustrate good practical forms thereof.

In the drawings Fig. 1 is a perspective view of the upper portion of a double spindle shaper provided with the guards of the present invention, one guard being raised and the other lowered.

Fig. 2 on an enlarged scale is an end view of the shaper of Fig. 1 with parts in section;

Fig. 3 is a vertical sectional view through a bumper to be described;

' Fig. 4 on a further enlarged scale is a perspective view of a shaper cutter and the associate guard;

Fig. 5 is a top plan view of the shaper table showing modified means for controlling the guard operating valve.

Fig. 6 is a verticalsectional View taken on the line 6-6 of Fig. 5;

Fig. 7 is an enlarged sectional view through the guard actuating valve;

Fig. 8 is a side elevation of the valve of Fig. 7 provided with means for regulating the exhaust; and

Fig. 9 is a vertical sectional view through adapted to be actuated by the double spindle shaper of well known construction.

The shaper shown consists of a supporting base 10 provided with the work supporting table 11, and extending upwardly through the table are the usual spindles 12 and 13 having the cutters 14. The spindles are driven in opposite directions at high speed by belts or motors as desired, and the work rests upon the table 11 while it is being acted upon by a cutter. Usually the work such as 15 which is to be presented to a cutter is bolted or otherwise secured to a form 16 that rests upon the table and the outer periphery or profile of the form 16 may act as a guide for determining the depth of cut, in a well known manner.

hen a shaper spindle is provided with a long or large cutter the spindle may vibrate to an objectionable degree while the cutter acts upon the work, and it is therefore common to provide each spindle with an overhead steady bearing for the spindle top. This steady bearing when used is mounted upon a post 1' positioned back of a cutter and having a base plate 18 that may be rigidly secured to the table 11 by bolts 19.

The construction so far described is well known in the art, but is utilized in carrying out the present invention to support the cutter guard and guard operating means which will now be described.

Each of the rotating cutters 14 is provided with a guard 20 which is preferably curved as shown so that it will practically surround the cutter, and the guard may be formed of sheet metal. In the construction shown each guard 20 is mounted for vertical sliding movement so that it may be lowered about a cutter to protect the latter, or raised above the cutter to permit engagement of the work with the cutter. The guards 20 are conveniently supported for vertical sliding movement by providing the post embracing collars 21 and 22 having the projecting arms 23 and these collars may be rigidly secured to the usual bearing supporting posts 17 by tightening the clamping bolts 24, 25. The arms 23 support the guide rods 26, and the guard 20 is provided at its inner face with the rod receiving brackets 27 which slidably secure the guard 20 to the guide rods 26.

When a guard 20 is in its lowered position as shown to the left in Fig. 1, the low 1' portion of the guard is spaced only a slight distance from the face of the table so that it will completely protect the cutter, and the guard may be supported in this lowered position by the brackets 27 resting upon the lower arms 23.

In the embodiment of the invention illustrated the weight of the guard 20 is relied upon to move the guard downward to its cutter protecting position when the means for holding it elevated is released. The arrangement is such that the guard normally remains in the lowered position in which it is shown at the left in Fig. 1. It is therefore necessary to raise the guard before the work is engaged with the cutter, and an important feature of the present invention resides in means for automatically raising the guard as the work approaches the cutter, and for lowering the guard as the work is moved away from the cutter.

This is accomplished, in accordance with the embodiment of the invention illustrated, by employing a cylinder having a piston for operating the guard 20, and valve controlled means is provided for admitting air under pressure to the cylinder and for exhausting it therefrom. The arrangement is such that the valve that shifts the guard is controlled by the movement of the work toward and from the cutter.

The guard 20 may be raised by a rocking lever 28 one end of which is secured by a pivot pin 29 to a projection 30 that extends upwardly from the upper collar 22. The lever 28 has the frontwardly extending arms 31 to which the guard 20 is connected by the links 32.

The rocking lever 28 is elevated to lift the guard 20 by an operating rod 83 which extends upwardly through the hollow post 17 and downwardly through an opening in the table 11. The upper end of the rod 33 is pivotally secured to the lever 28 by a bolt 34 and the lower end of the rod 33 is connected to a piston rod 35 that extends into a cylinder 36 which is supported by a bracket 37 beneath the table 11. The piston rod 35 has a piston 38 adapted to slide within the bore of the cylinder, and secured to the under face of the piston 38 is a cup-shaped washer 89 (see Fig. 9).

Air under pressure is supplied to the lower end of the piston 36 by the pipe 40. The arrangement is such that when air is forced into the cylinder 36 the piston 38 will be forced upwardly to act through the rod 33 and bracket 38 to lift the guard 20, and the guard will be held in its elevated position as long as the air pressure is maintained in the cylinder. As soon as the air pressure within the cylinder 86 is relieved the guard will drop to its cutter protectin position.

The upward movement of the guard is conveniently limited by a rod 41 extending upwardly from the upper collar 22 and this rod is provided with a yielding bumper adapted to be struck by the portion 42 of the bracket 28. The bumper (see Fig. 3) consists of a hollow casing 43 having threaded engagement with the rod 41 for adjustment lengthwise of the rod and inthe casing 43 is a coiled spring 44 which exerts a continuous downward pressure upon the sliding element 45. The casing 43 is secured in the desired position of adjustment along the rod 41 by tightening the lock nut 46.

In order to raise and lower the guard 20 by the mechanism so far described, air under pressure is supplied from any suitable source by the pipe 47 which is connected to the casing 48 of the control valve by the pipe 49 and the flow of air to the valve casing 48 is preferably controlled by a needle valve 50 that may be adjusted as desired to vary the speed at which air will be forced into the cylinder 36 to lift the guard 20.

The valve casing 48 is connected to the cylinder 36 by the pipe 40 and the construction of the valve casing 48 is best shown in Fig. 7 wherein it will be seen that the valve casing has a vertical plunger 51 which is normally held elevated by the coiled spring 52. The plunger 51 has a reduced portion 53 and an upper portion 54 and to the upper portion the operating button 55 is secured by means of a pin 55.

The valve casing may be mounted in a hole in the table 11 so that the upper end of the casing 48 will be flush with the upper face of the table, and the button 55 extends upwardly a slight distance above the face of the table and is adapted to be engaged and held depressed by the lower face of the form 16 as long as the work is adjacent the cutter 14.

As long as the valve plunger 51 is elevated as shown in Fig. 7, air supplied to the lower port 56 by the pipe 49 is confined in this port by the plunger, but when the plunger is depressed so that the reduced portion 53 thereof is opposite the port 56, then the air under pressure will pass from pipe 49, port 56 and port 57 to the pipe 40 and through the latter into the cylinder 36 to elevate the piston 38, and this pressure upon the piston will be maintained as long as the button 55 is depressed, thus holding the guard 20 elevated.

When the form 16 is removed from the work the plunger 51 will move upwardly under the action of the spring 52 to the position of Fig. 7. This will close port 56 and permit the air in the cylinder 36 to escape through the pipe 40, port 57 and upper port or ports 58.

In some cases it may be desirable to employ a single exhaust port 58 and provide this port with a valve 59 adapted to be ad jueted to vary the speed at which air may escape from the cylinder 36 to thereby vary the speed at which the guard 20 will be lowered.

While air has been described herein as the actuating medium it will be understood that various fluids either liquids or gases may be employed to this end, and that various forms of valves may be employed to control the action of the fluid upon the guard shifting means.

It may be desirable to depress the valve button 55 from a plurality of points adjacent the cutter,

and this may be accomplished by providing the pivoted lever or yoke 60 which may be pivotally mounted at 61 beneath the table 11 so that an intermediate portion of this lever will rest the lever may have the spaced pins 62 that extend upwardly through holes in the table so that ifpressure is exerted downwardly upon any one of the pins 62 the lever 60 will be depressed to depress the button 55. WVhen this construction is employed the valve casing 48 may be supported by a bracket 63.

It willbe seen from the foregoing that the movement of the guard 20 to and from the cutter protecting position is readily controlled by compressed air, and that the speed at which the guard is raised or lowered may *be varied as desired by changing the adjustment of the valves 50 and 59.

It should be noted that the guard supporting brackets or collars 21 and 22 are positioned near the opposite ends of the post 17 and that the guard operating rod 33 extends upwardly through the hollow post. This construction is important since it leaves the intermediate portion of the post 17 free to receive the cutter s-teadying guard as heretofore, and as a result the post 17 may perform the double function of supporting the usual cutter steadying device and the cutter guard.

What is claimed is 1. In combination with a shaper having a work supporting table, a power driven cutter and .a hollow cutter-steadying post; a cutter guard. a frame fastened to said post for supporting the guard for sliding movement to and from the cutter protecting position, a guard operating lever pivotally supported by said post and connected to the guard, a rod extending upwardly through said post to operate the lever, a fluid operated piston mounted below the table to actuate the rod, and a valve for controlling the operating fluid supplied to said piston.

2. In combination with a shaper having a work supporting table, a power driven cutter and a hollow cutter-steadying post; a cutter guard, a frame fastened to said post for supporting the guard for sliding movement to and from the cutter protecting position, a rod extending upwardly through said post and operatively connected to the guard, a fluid operated piston for shifting said rod, and a valve for controlling the operating fluid supplied to the piston and positioned to be actuated by presenting work to the cutter.

3. In combination with a shaper having a work supporting table, a power driven cutter and a hollow cutter-steadying post; a cutter guard. a frame fastened to said post to support the guard for sliding movement to and from the cutter protecting position, a guard operating lever pivotally supported by said post and connected to the guard, a rod slidable within said hollow post and connected upon the button 55 and to the lever to actuate the guard, stop mechanism for limiting the upward movement of the guard including a yielding buffer and means for supporting the same in different positions of adjustment, a fluid operated piston mounted below the table to actuate the rod, and a valve for controlling the operating fluid supplied to the piston and positioned to be actuated by presenting Work to the cutter.

In testimony whereof, I have signed my name to this specification.

ALPHONZO WHITE.

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