US2895518A - Shaper guard with auxiliary finger protectors - Google Patents

Description

July 21, 1959" H. s. RHETT 2,895,518

SHAPER GUARD WITH AUXILIARY FINGER PROTECTORS Filed April'll; 1957 INVENTOR I ATTORNEY 5 United States Patent SHAPER GUARD WITH AUXILIARY FINGER PROTECTORS Haskell S. lRhett, Wilmington, NC. Application April 11, 1957, Serial No. 652,152

8 Claims. (Cl. 144-251) This invention relates to a guard or hand protector for use in power machine tools of the type in which a workpiece is manually traversed across a cutter head, comminutor or other cutting device.

It is important in such tools to provide guard means which is not only effective for its purpose generally speaking but which also permits a clear view of the work and of the cutter head and which avoids interference with the use of the machine. Otherwise, it has been found that the guard will often be considered by the workman as a nuisance and either removed or placed in inoperative position.

A further highly desirable end and yet one which has not been successfully attained by the prior art is to so arrange and construct the guard that it may progressively close behind the trailing end of the workpiece as the latter completes its traversal of the cutter head and thus effectively protect the workmans hands and fingers at this time to prevent them from coming into engagement with the cutter head.

The present invention has been conceived with the foregoing considerations in mind and thus has as its primary objects to provide such a guard mechanism which operates without obstructing or interfering with the use of the machine while also permitting a clear view of the workpiece and the cutter head at all times, which progressively closes behind the trailing end of the workpiece, and yet which operates efiiciently to serve its protective function at all times.

It is a further object to provide such a guard which is particularly adapted for application in novel manner to the conventional shaping machines such as are well known and commonly used in wood working, though it will be apparent that the invention is by no means restricted to this particular application.

It is a still further object to provide such a guard which is adapted for actuation by gravity, and also to so construct the guard that it is reversible or, in other words, may be alternatively positioned on the shaper or other machine to permit feeding of the workpiece from either the right or the left hand side of the cutter head.

In order to attain the foregoing ends the invention broadly comprises the concept of supporting a main guard element over the said table of the machine and in front of the cutter head for vertical movement. The guard is urged by gravity toward the feed table but suitable means are provided for limiting its downward movement so that it is supported in normally spaced relation above the feed table, whereby a plurality of depending vertically retractable guard fingers may be suspended and guided from the main guard above the feed table in front of the cutter head and in a path generally along the direction of feed movement of the workpiece. These guard fingers are limited in their downward projection movement, to be normally supported with their lower ends at the level of or slightly above the feed table but in such manner as to positively prevent movement of an operators fingers into engagement with the cutter head.

In association with the the guard and/or its supporting means there is preferably provided a cam disposed for engagement with the leading end of the workpiece fed toward the cutter head to raise both the guard and its depending guard fingers suificiently to permit entry of the workpiece beneath the fingers. Such cam or cam means is preferably disposed just in advance of the cutter head whereby it may descend immediately upon passage of the trailingend of the workpiece from therebeneath to function itself in the manner of a guard ob structing movement of the operators fingers toward the cutter head with the trailing end of the workpiece. Thereafter, such. of the guard fingers as are engaged with and retracted by the workpiece will be successively projected downwardly by gravity to close behind the workpiece and thus afford the desired protection. In accordance with the invention the. guard fingers will normally be relatively spaced apart suificiently to permit a clear view of the cutter head and workpiece therethrough, but their spacing will be insufiicient to permit contact of the operators hands or fingers with the cutter head by movement between adjoining guard fingers.

A still further important feature of the invention consists in utilizing a swingably mounted arm for supporting the main guard. This arm is swingably mountable see selectively on either side of the cutter head for vertical movement and has both the main guard and a pair of alternately operative cam elements disposed on said arm symmetrically to and on opposite vertical sides of its major longitudinal axis, to permit feeding of the work.- piece from either side without adversely affecting its mode of operation.

A guard mechanism incorporating the above enumerated features and advantages is exemplified in the ac-. companying drawings in which:

Figure 1 represents a front elevation of a portion of a conventional shaperhaving the guard applied thereto in accordance with the invention, and showing the guard in the position assumed by it midway of the progress of the workpieces across the cutter head.

Figure 2 is a View similar to Figure 1 showing the positions assumed by the guard and its several parts during completion of the traversal of the workpiece, after the trailing end of the workpiece has cleared certain of the guard fingers.

Figure 3 is a plan view of the structure shown in Figures 1 and 2.

Referring now in detail to the accompanying drawings, the invention is there shown as applied to a conventional shaper such as is used in woodworking operations. The shaper is of the class including a horizontal work sup.- porting and feeding table 10, along the rear edge of which extends a vertical fence 12 for guiding a workpiece W in its feeding or traversing movement over a usual rotary cutter head 14,. It will be seen that the cutter head 14 s carried for rotation on and driven by a vertical drive shaft 16, the latter being supported by the table 10 and driven from any suitable power source in a manner well known in the art and constituting no part of the instant invention. The cutter 14 which broadly exemplifies any usual type of cutting or comminuting element is positioned in a gap or opening 18 in the fence 12 with its several knives 14' disposed for successive movement through the gap and into operative cutting engagement with the workpiece as the latter is fed along the fence 12 in guiding engagement with the front face thereof.

In the drawings only such portions of the feed table 10 and fence 12 are shown as are necessary to permit illustration of the manner in which the instant invention is applied thereto. In such application the inven-- tion comprises a main guard 20 and means such as the 3 V vertically swingable arm 22 supporting it in vertically spaced relation above the feed table 10. From a broad standpoint the arm 22 may be considered as merely an exemplification of-any means supporting the guard 20 for vertical movement. The arm 22 is pivotally mounted on the feed table for such vertical swinging movement by means of a pivot 24 connecting it to the fence 12, whereby the swinging of the arm '22 will be in a plane parallel and generally contiguous to the front face of the fence, with the free end of the arm in the present embodiment terminating adjacent the infeed side of the cutter head 14 and the guard 20 itself projecting from this free end completely across both the cutter head and the gap 18 through which it operates.

' Preferably the guard 20 is arcuately curved as shown in Figure 3 to extend substantially concentrically about the rotational axis 16 of the cutter head and is provided with a similarly arcuately arranged series of vertical bores through which are vertically slidably disposed a series of normally depending guard fingers 26. The downward swinging movement of the arm 22 and guard 20 is limited in any suitable manner so that the guard 20 will normally be positioned in spaced relation above the feed table 10 in a generally horizontally extending position. Suitable movement limiting means for this purpose are shown in the instant embodiment as comprising a depending supporting foot 28 at the free end of the arm 22 and constituting an integral part thereof for abutting engagement with either the table 10 or the upper surface of the workpiece W.

' In order that the foot 28 may be raised out of the path of the workpiece W incident to feeding movement of the latter, the arm 22 is provided with suitable cam means exemplified by the integrally formed cam portion or surface 30, which in the present embodiment merges with or at least extends to the lower end of the foot 28. The downward projection of the several fingers 26 is restricted in any suitable manner so that they can in no event project downwardly beyond the cam means 30 and thus will be raised clear of the workpiece with the cam 30 and supporting foot 28 to avoid obstructing the feed movement of the workpiece. To this end the several fingers 26 in the instant embodiment are provided at their upper ends with lateral projections which may conveniently comprise merely laterally bent portions 32 arranged to abut against the upper surface of the guard 20.

3 It will be seen that the guard 20 and its supporting arm are so arranged that the pivot 24 of the arm is on the left hand side of the cutter head and the cam surface 30 is directed toward such left hand side, all to the end that the guard means of the invention may properly coact wtih a workpiece W which is fed toward the guard from the left as indicated by the arrow in Figure 1. However, in order that the guard may be mounted to cooperate with a workpiece which is fed in the reverse direction or from the right to the left, the arm 22 may be provided with an adidtional supporting foot 28 together with an associated cam or cam surface 30'. These are symmetrically arranged on the opposite side of a generally horizontal axis of symmetry corresponding to the longitudinal axis of the arm 22 and the arm in the present embodiment is provided at its pivot end with an additional pivot hole 34 whereby it may be selectively pivotally mounted as indicated in broken lines in Figure l with the elements 28 and 30' directed downwardly for operative engagement with the workpiece during feeding of the latter from right to left. In this connection it will be noted that the guard 20 itself in the present embodiment is mounted on" and extends along the said axis of symmetry to be supported equidistantly above the table and/or workpiece in either position, and the fingers 26 are formed with the stops or limit means 32' as well as the aforementioned limit means 32 for coaction with the guide 20 in similar manner in either Of the selective operative positions of the guard.

Thus in the operation of the invention it will be apparent that as the workpiece W is fed from left to right along the fence 12 toward the cutter head, its leading end will engage the cam surface 30 to raise the guard 20 and its several fingers 26 together with the foot 28, so that the workpiece may move freely beneath the depending lower ends of the fingers as it is fed across the cutter head 14. During most of such feeding movement, the fingers normally are supported by their stops 32 with their lower ends 32 slightly above the workpiece. The depending cam 30 and/or its foot portion 28, togetherwith the guard fingers 26 and guard 20, serve effectually to prevent contact of the operators fingers with the cutter head despite the fact that the arrangement and spacing of the fingers 26 is such as will permit a clear view of the cutter head and of the progress of the cut. As will be apparent from Figure 2 of the drawings, as the trailing end of the workpiece W moves from beneath the cam 30 and its supporting foot 28, the latter will immediately descend into engagement with the table 10, providing an obstruction to prevent movement of the operators fingers toward the cutter head. Thus the elements 28 and 30 will supplement the action of the depending fingers 26 and their supporting guard 20. Moreover, as the arm and its elements 28, 30 descend into engagement with the table to close behind the workpiece, the several fingers 26 will be retracted upwardly by engagement of their lower ends with the upper surface of the workpiece. At least this will be true as to such of the fingers 26 as are in vertical registry with the workpiece, although in cases Where the workpiece is relatively narrow it is contemplated that certain of the fingers 26 which are comparatively remotely spaced from the fence 12 will remain to one side of and thus out of contact with the workpiece and thus will remain fully downwardly projected beside the workpiece to effectually carry out their protective function.

During continued movement of the workpiece from beneath such of the fingers 26 as are in engagement with it, these fingers will, of course, successively be projected by gravity to close behind the trailing end of the workpiece and thus afiord the fullest degree of protection, such as will prevent contact of the cutter head by operator-s' fingers. In order to increase the degree of visibility alforded by the guard structure of the invention, both the arm 22 and the guard 20 may conveniently be constructed of a clear transparent plastic or other material while the guard fingers 26 may be conveniently and economically formed from wires or wire rods of any suitable comparatively rigid material.

Although I have shown and described only the preferr'ed embodiment of my invention I recognize that the invention is capable of'other embodiments and that its several details may be varied all without departing from the invention. Accordingly, the drawings and description herein are to be considered as merely illustrative in nature and not as restrictive.

Having thus described the invention, what is claimed as new'and desired to be secured by Letters Patent is:

1. In a machine of the class wherein a workpiece is traversed over a horizontal feed table in operative engagement with a rotary cutter head on said table, said feed table including a rectilinear fence extending in opposite horizontal directions from said cutter head and to one side of the operative peripheral cutting portion of said head for guiding the work piece along said table for feeding movement in a predetermined direction in operative engagement with the cutter head, said cutter head rotating about a vertical axis, the combination comprising a main guard, means supporting said main guard for vertical movement above the feed table abreast of the cutter head with respect to said feeding movement and on the opposite side of said peripheral cutting portion from the fence, said guard normally resting on said table and having a cam surface fixedly connected to said guard in advance of the cutter head for engagement by a workpiece incident to feeding movement of the work piece toward the cutter head and a plurality of guard fingers carried by said main guard for relatively independent vertical sliding movement, said fingers being relatively spaced apart in said predetermined direction to permit a clear view of the work piece and to successively project behind the work piece as the latter is fed past the cutter head, and movement limiting means associated with the respective fingers for preventing their movement below said cam surfacev 2. The combination of claim 1 wherein said means supporting the main guard comprises a supporting arm carrying said guard at its free end, and pivotally supported on the fence at its other end for vertical swinging movement parallel to said fence.

3. The combination of claim 2 wherein said cam includes a supporting foot normally resting on the table in advance of said cutter head with respect to the said feeding movement, and supporting the guard in spaced re lation above said table.

4. The combination of claim 1 wherein said guard is curved arcuately about the rotational axis of the cutter head, and said fingers are arranged in an arcuate series thereon.

5. The combination of claim 1 wherein said means supporting the main guard comprises a supporting arm carrying said guard at its free end, means for selectively pivotally mounting the arm in alternate operative positions on said fence on either side of the cutter head for fingering movement parallel to the fence, cam means being symmetrically mounted on opposite sides of the longitudinal axis of said arm for cooperation with the work.- piece in either of said positions, said movement limiting means comprising lateral projections at opposite ends of the fingers for engagement with said main guard.

6. In a machine of the class wherein a workpiece is traversed over a horizontal feed table in operative engagement with a rotary cutter head on said table, said feed table including a rectilinear fence extending in opposite horizontal directions from said cutter head and to one side of the operative peripheral cutting portion of said head for guiding the work piece along said table for feeding movement in a predetermined direction in op erative engagement with the cutter head, said cutter head rotating about a vertical axis, the combination comprising a main guard, means supporting said guard for vertical movement above the feed table abreast of said cutter head in said predetermined direction and on the opposite side of said peripheral cutting portion from the fence, cam means carried by said supporting means on the in-. feed side of the cutter head for engagement by a workpiece to raise the guard, a plurality of guard fingers guided for free vertical movement on said guard, and disposed in a series extending generally along the path of feed of the workpiece and spaced apart relative to each other in said predetermined direction, and movement limiting means associated with the respective fingers for preventing their movement below said cam means.

7. The combination of claim 6 wherein said main guard is formed with a series of vertical guide holes slidably receiving said fingers and permitting their downward projection by gravity, said fingers having lateral projections at their upper ends to limit such projection.

8. The combination of claim 6 wherein said means supporting the guard comprises a rigid arm pivotally mounted on the fence for vertical swinging movement parallel to the fence, said cam means depending from the arm and normally engaging the table to support the guard in raised relation thereabove.

References Cited in the file of this patent UNITED STATES PATENTS 909,116 Rasmussen Jan. 5, 1909 925,114 Loefl ler June 15, 1909 1,157,109 Howe Oct. 19, 1915 1,217,550 Alwine Feb. 27, 1917 1,801,256 Auld Apr. 21, 1931 2,603,252 Petersen July 15, 1952 2,642,104 Brown June 16, 1953 2,804,892 Peterson Sept. 3, 1957 FOREIGN PATENTS 100,350 Austria June 25, 1925 105,543 Switzerland July 1, 1924

Images