US3859950A

US3859950A - Safety guard for shaping tool

Info

Publication number: US3859950A
Application number: US396602A
Authority: US
Inventors: Daniel R York
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-09-12
Filing date: 1973-09-12
Publication date: 1975-01-14
Anticipated expiration: 1992-01-14

Abstract

A guard for a table-mounted hand shaping tool includes a shield comprising a U-shaped upstanding panel mounted on a pair of rearwardly extending support members. At rest on the table the Ushaped panel surrounds the forward and side portions of a cutterhead, which extends upwardly above the surface of the table, while leaving the rearward portion open. The support members are pivotally mounted on upright brackets fastened to the table for fore and aft pivotal movement about an axis generally parallel to the plane of the table. A pair of transverse members are mounted on the support members. A pneumatic cylinder is fixedly mounted to the pair of transverse members. The pneumatic cylinder has a reciprocable piston with a rod attached thereto and extending downwardly from the cylinder. The free end of the rod carries a captive ball socket which bears against the table surface. Upon remote actuation of the pneumatic cylinder, the piston translates in the cylinder and causes the cylinder to rise and consequently causes the entire guard assembly to pivot upwardly and rearwardly about its pivotal mounting axis, thereby allowing a workpiece to engage the cutterhead. If desired, the guard can be pivoted to a remote rearward position for ready access to the cutterhead for changing blades and maintenance.

Description

United States Patent [191 York [ 51 Jan. 14,1975

[ SAFETY GUARD FOR SHAPING TOOL [76] Inventor: Daniel R.York,9l5l E. 52nd,

Tacoma, Wash. 98424 [22] Filed: Sept. 12, 1973 [21] Appl. No.: 396,602

Primary Examiner-Andrew R. Juhasz Assistant Examiner-W. D. Bray Attorney, Agent, or Firm-Christensen, OConnor, Garrison & Havelka [57] ABSTRACT A guard for a table-mounted hand shaping tool includes a shield comprising a U-shaped upstanding panel mounted on a pair of rearwardly extending support members. At rest on the table the U-shaped panel surrounds the forward and side portions of a cutterhead, which extends upwardly above the surface of the table, while leaving the rearward portion open. The support members are pivotally mounted on upright brackets fastened to the table for fore and aft pivotal movement about an axis generally parallel to the plane of the table. A pair of transverse members are mounted on the support members. A pneumatic cylinder is fixedly mounted to the pair of transverse members. The pneumatic cylinder has a reciprocable piston with a rod attached thereto and extending downwardly from the cylinder. The free end of the rod carries a captive ball socket which bears against the table surface. Upon remote actuation of the pneumatic cylinder, the piston translates in the cylinder and causes the cylinder to rise and consequently causes the entire guard assembly to pivot upwardly and rearwardly about its pivotal mounting axis, thereby allowing a workpiece to engage the cutterhead. If desired, the guard can be pivoted to a remote rearward position for ready access to the cutterhead for changing blades and maintenance.

10 Claims, 3 Drawing Figures PATENTED JAN 1 41875 SHEET 10F 2 wmllmip PATENTEDJAN 1 4|975 sum 2 or 2 SAFETY GUARD FOR SHAPING TOOL BACKGROUND OF THE INVENTION The present invention relates to a safety device for a rotating cutterhead mounted on a table and, more particularly, to a safety shield for a table mounted hand shaper.

Machines known as hand shapers are generally used in the woodworking art to shape the edges'of planar sections of wooden workpieces. Such edges are shaped by free hand manipulation of the workpiece or by following a preshaped form. Generally, hand shapers are mounted on a table having a planar top surface and have a cutterhead shaft extending upwardly above the surface of the table at generally right angles thereto. A cutter knife is attached to the portion of the shaft extending above the surface of the table. Generally these knives are very securely fastened to the shaft by means of a threaded retaining nut.

Upon failure of the knife, the shaft or some other catastrophic failure of the cutterhead, fragments occasionally separatefrom the cutterhead and are expelled in a direction tangential to the rotation of the shaft. Since these shaftsgenerally rotate atvery high speeds, on the order of six :to ten thousand rpm, the knives upon acci dental separation from the shaft travel at great velocities presentinga great potential dangerto the operators andother individualsin the vicinity of the hand shapers. Based on .past experience, it has been learned that knives generally will separate from the shaft during start-up,whenthe shaft is accelerating fromthe rest to operating speed,andduring shutdown, when the shaft is slowing from operating speed to rest. The knives may separate fromthe shaftwhen the machine is running at operating speed, but when no workpiece is present in front of the knife. When the knife .is operating on a workpiece the workpiece itself provides a sufficient guard to prevent injury from accidental separation of knives from the shaft.

In order to provide a machinewhich is safe for an operator to manipulate during periods of high stress on the cutterhead,it is desirable to employ acutterguard which will prevent knives from injuringpersons in the vicinity of the machine should they accidentally separate fromthe shaftSeveral prior art means for solving this safety problem "have been suggested; however, most of these require large and cumbersome mechanism for operation and are expensive and difficult to operate. Furthermore, it is desirable to obtain some measure of protection during actual manipulation of a workpiece against the cutterhead. Priorart guards have not provided any substantial amount ofprotection during this period.

A broadobject of .thepresent invention is to provide a safety device for. arotatingcutterhead mounted ona table which fulfills the foregoingdesirable attributes. Further objectsofthepresent invention are toprovide a guard whichraises above the-cutterhead to aheight sufficientto provide agood view of thecutterhead and workpiece being manipulated while simultaneously providing a-measure of safety from blades which may accidentally separatefrom the shaft; to provide aguard which is capableof pivoting rearwardly out of the vicinity of the cutterheadin orderto allow ready access to the head for maintenance and replacement; to provide a guard whichin its operativejposition during shaping rests only a small distance above the workpiece, which distance can be adjusted to allow for different workpiece thicknesses, thereby providing maximum protection during operation of the machine; to provide a cutterhead guard which can be easily installed on existing shapers; to provide a cutterhead guard which can be remotely operated; to provide a cutterhead guard which is relatively inexpensive to manufacture and which requires little maintenance; and to provide a power means for operating the guard or safety device from an energy source readily available in most woodworking shops.

SUMMARY OF THE INVENTION The foregoing objects and other objects which will become apparent upon reading the following specification are fulfilled by a novel safety device for a rotating cutterhead mounted on a table. The device includes a movable guard means having a forward wall portion and spaced sidewall portions extending rearwardly therefrom. Mounting means is provided to locate the guard means in a first position in which the wall portions are located adjacent to the table and extend upwardly therefrom to define a region surrounding the front and sides of the cutterhead. The mounting means is capable of pivoting the guard means upwardly about an axis parallel to the table and transverse to the rearwardly extending side wall portions to a second position in which a workpiece can be slid under the guard means for access to the cutterhead. In the second position the guard means still providesprotection by surrounding the portion of the cutterhead extendingabove BRIEFDESCRIPTION OF THE DRAWINGS A betterunderstanding of the present invention can be derived by reading the ensuing specification in conjunction with the accompanyingdrawings wherein:

FIG. 1 is an isometric view illustrating the guard assembly of the present invention from the rear aspositionedover the .work table of a wood shaping tool when no workpiece is present;

FIG. 2 is a plan view of the assembly ofFIG. l;an

FIG. 3 is a side elevation view of the assembly of FIG. 1 showing the guardin a second position when artworkpiece is beingshaped and ina thirdposition (in ghost outline) .providing easy access to the cutterhead for maintenance.

DESCRIPTION OF PREFERRED EMBODIMENT FIGS. 1, Zand 3 portray a cutterhead l0 mounted on a table 12 formilng part of a powered hand shaping tool of the type used to shape theedges and sides of wooden beams boards, panels and the like. The front of the shaping tool is at the left side as viewed in all FIG- URES..In operation a workpieceis moved into the cutterhead 10 from the front and is moved generally from right to left by an operator to shape the edge of the workpiece. The guard assembly, generally designated 14, is installed onthe table 12. It has four functional parts which include mounting brackets 16, frame 18, shield 20 and a pneumatic cylinder operating mechanism'22.

The frame 18 is the primary structural member of the guard assembly 14, providing support for the shield 20 and fixing its positions relative to the cutterhead 10. The frame has two tubular arms or rods 32'which extend rearwardly from the shield 20 and which are welded or otherwise suitably affixed to the sidewalls thereof. The arms 32 are transversely interconnected by parallel bars 34. Mutually aligned stub shafts 28 are affixed in transverse relationnship to the rearward ends of the tubular arms 32. Mounting brackets 16 are bolted to the rear top surface of table 12. In this location the brackets 16 do not interfere with the workpiece when it is engaged with the cutterhead 10. The brackets 16 have axially aligned mounting holes 26 which receive the stub shafts 28, thereby establishing a pivotal axis 30 about which the shield and frame can pivot while being lowered and raised.

The shield 20 has a generally U-shaped cross-section when looking downwardly from the top. It has a for ward wall and spaced sidewalls extending in a smooth curve rearwardly from the forward wall. The walls exend generally perpendicularly upwardly from the surface of the table 12 to form a region sufficiently large to enclose the cutterhead 10 on three sides. For most applications the rearward, portion of the shield is open since the rear side of a shaper of this type is usually abutted against a wall or-has an integral rear shield. The shield 20 is fabricated from sheet metal or other suitable impact resistant material. If desired the shield 20 can be constructed from a transparent high impact plastic to allow the operator to visually monitor the status of a workpiece at the cutterhead 10. The stub shafts 28 are secured to the brackets 16 with cotter pins 36.

By appropriately choosing the length of the arms 32 and the location of the brackets 16, the shield 20 can be located so that in a lowered position, as shown in FIG. 1, the bottom of the shield 20 is located below the plane of rotation of the knives on the cuutterhead 10. A spacer 38 is attached to the bottom of the sidewalls of the shield 20 and rests on the top surface of table 12 of the shaping tool. The spacer supports the shield 20 in its lowered position. The shield is placed in the lowered position when a workpiece is not engaged with the cutterhead 10, allowing the guard assembly 14 to provide maximum protection from blade separataion as well as preventing inadvertent contact with the rotating cutterhead itself.

Support brackets 40 mounted on the transverse parallel bars 34 provide a base through which a pneumatic actuating cylinder 42 is attached to the frame 18. When energized, the actuator 42 functions to lift the guard assembly 14 from the surface of the operating table surface 12 sufficiently far to allow a workpiece 44 (FIG. 3) to be inserted under the bottom of shield 20 and to engage the cutterhead 10. A push-type pneumatic actuator is preferably employed. A rod or plunger 46, connected to a piston in the cylinder 42, extends from the cylinder toward the table 12.. The plunger 46 terminates at its lower end in a captive ball and socket fixture 48 which reduces the frictionbetween the plunger 46 and the table surface 12 to a negligible value as the assembly is cycled about its pivotal axis. When pneumatic pressure is applied to the cylinder, it rises upwadly carrying the frame 18 and shield 20 along. the pneumatic actuator cylinder 42 can be actuated by a foot-operated valve or the like (not shown) via an air hose 58. Other suitable actuators can be used as desired.

A pair of studs 52 is affixed to a plate 50 associated with the ball fixture 48. The studs 52 are located parallel to the plunger'46 and slidably engage holes 54 in support brackets 40. The studs are effectively a part of the plunger 46 and extend and retract through the holes 54 in the brackets 40 conjunctively with the plunger 46. The travel of the studs 52 through the bracket holes 54 is adjustably limited by the knurled nuts 56, which are threaded on the ends of the studs 52. Turning the nuts toward the free ends of the studs-allows'the plunger 46 to extend further toward the table 12, thereby allowing the guard to be raised higher. Turning the nuts 56 in the opposite direction restricts the translational distance of the plunger 46 to its shorter stroke, thereby reducing the lifting distance.

The guard assembly 14 as illustrated in FIG. 1 shows the actuator 42 in a deactivated position with the spacers 38 resting on the table 12 to provide maximum protection for the operator. FIG. 3 illustrates the guard assembly 14 as it appears with foot pedal (not shown) depressed thereby energizing the penumatic actuator 42. The plunger 46 is extended, elevating the guard assembly l4 rearwardly and upwardly about pivotal axis 30. When the shield 20 is elevated, a workpiece 44 can be applied to thecutte'rhead 10. Raising the guard'assembly 14 in this manner affords the operator physical and visual access to the cutterhead 10 while maintaining protection during the shaping operation.

As shown in ghost outline in FIG. 3, the guard assembly 14 can be manually pivoted beyond its raised operational position in the direction indicated by arrow 60 to a stowed position to allow accessto the cutterhead for maintenance. In the stowed position a rod 62 affixed to the rear portion of arm 32 and extending perpendicularly therefrom bears against the table 12 to limit the rearward travel, of the guard assembly 14.

The present invention has been described in relation to a preferred embodiment. One of ordinary skill in the art will be able to effect various alterations to substitutions of equivalents in, and other changes to that embodiment without departing from the orginal concept disclosed herein. It is therefore intended that the present invention be limited only by the definition contained in the appended claims.

What is claimed is:

l. A safety device for a rotating cutterhead mounted on a table comprising:

guard means having a forward upright wall portion and spaced upright sidewall portions affixed to and extending rearwardly from said forward wall portion, said, guard means defining a region enclosed on at least three sides, said region being sufficiently large to enclose a cutterhead protruding from said.

table, said guard. means including a support member affixed thereto and extending rearwardly there-,

from, v mounting means for attaching said support member to said table for selective upward and rearward piv- ,1 otal movementabout an axis generally parallel to said table, said axis being located rearwardly of said cutterhead, said mounting means capable of supporting said guard means for movement from a first position surrounding said cutterhead to a second position located above said first position wherein a workpiece can be moved across said table and under said forward wall and sidewall portions and from said second position to a third stowed position wherein at least a substantial portion of said guard means is positioned, relative to said first position of said guard means, rearwardly of said axis.

2. The safety device of claim 1 wherein said forward wall portion and said sidewall portions comprise a panel of generally U-shaped cross-section extending upwardly from said table, said sidewall portions terminating in rearward, upright edges, said panel being open between the rearward edges of said sidewall portions.

3. The safety device of claim 2 wherein said support member comprises an arm attached to and extending rearwardly from each rearward edge of the sidewall portions of said U-shaped panel, and wherein said mounting means comprises bracket means for attachement to said table, said bracket means capable of extending upwardly from said table, and mutually aligned stub shafts extending generally parallel to said table and transversely from each of said arms, said stub shafts cooperating with said bracket means to mount said arms for pivotal movement about said axis.

A safety device for a rotating cutterhead mounted on a table comprising:

guard means having a forward upright wall portion and spaced upright sidewall portions affixed to and extending rearwardly from said forward wall portion, said guard means defining a region enclosed on at least three sides, said region being suffiently large to enclose a cutterhead protruding from said table, said guard means including a support member affixed thereto and extendingrearwardly therefrom,

mounting means for attaching said support member to said table for selective upward and rearward pivotal movement about an axis generally parallel to said table, said mounting means capable of supporting said guard means for movement from a first position surrounding said cutterhead to at least a second position located above said first position wherein a workpiece can be moved across said table and under said forward wall andsidewall portions, and,

a fluid operated cylinder means mounted on said support member at a position forwardly of said axis, said cylinder means including a piston having a piston rod connected thereto and extending downwardly toward said table and having means on the free end thereof for bearing against said table, said cylinder thereby mounted for reciprocal movement toward and away from said table upon extension of said piston, thereby causing said guard means to pivot about said axis.

5. The safety device of claim 4 wherein said sidewall portions terminate in rearward upright edges, said support member comprising an arm attached to and extending rearwardly from each rearward edge of the sidewall portions and a transverse member affixed to and extending between said arms, said cylinder being affixed to said transverse member.

6. The safety device of claim 5 wherein said cylinder means includes means for adjusting the reciprocal travel distance of said piston rod.

7. The safety device of claim 4 wherein said means on the end of said piston rod comprises a socket connected to said piston rod and a ball mounted for rota tion in said socket for bearing against said table.

8. The safety device of claim 4 further comprising:

means operable from a location remote from said guard means and mounted thereon for actuating said cylinder means to move said guard means between said first and second positions.

9. The safety device of claim 1 further comprising:

an arm means rigidly connected to and extending upwardly from said support member, said arm acting as a stop for pivotal movement of said guard means when said guard means is moved to said third stowed position.

10. The safety device of claim 1 further comprising:

stop means attached to the bottom portion of said guard means for limiting the pivotal travel of said guard means downwardly toward said table about said axis thereby fixing the distance at which said guard means rests above said table in said first position.

Claims

1. A safety device for a rotating cutterhead mounted on a table comprising: guard means having a forward upright wall portion and spaced upright sidewall portions affixed to and extending rearwardly from said forward wall portion, said guard means defining a region enclosed on at least three sides, said region being sufficiently large to enclose a cutterhead protruding from said table, said guard means including a support member affixed thereto and extending rearwardly therefrom, mounting means for attaching said support member to said table for selective upward and rearward pivotal movement about an axis generally parallel to said table, said axis being located rearwardly of said cutterhead, said mounting means capable of supporting said guard means for movement from a first position surrounding said cutterhead to a second position located above said first position wherein a workpiece can be moved across said table and under said forward wall and sidewall portions and from said second position to a third stowed position wherein at least a substantial portion of said guard means is positioned, relative to said first position of said guard means, rearwardly of said axis.

3. The safety device of claim 2 wherein said support member comprises an arm attached to and extending rearwardly from each rearward edge of the sidewall portions of said U-shaped panel, and wherein said mounting means comprises bracket means for attachement to said table, said bracket means capable of extending upwardly from said table, and mutually aligned stub shafts extending generally parallel to said table and transversely from each of said arms, said stub shafts cooperating with said bracket means to mount said arms for pivotal movement about said axis. 4. A safety device for a rotating cutterhead mounted on a table comprising: guard means having a forward upright wall portion and spaced upright sidewall portions affixed to and extending rearwardly from said forward wall portion, said guard means defining a region enclosed on at least three sides, said region being suffiently large to enclose a cutterhead protruding from said table, said guard means including a support member affixed thereto and extending rearwardly therefrom, mounting means for attaching said support member to said table for selective upward and rearward pivotal movement about an axis generally parallel to said table, said mounting means capable of supporting said guard means for movement from a first position surrounding said cutterhead to at least a second position located above said first position wherein a workpiece can be moved across said table and under said forward wall and sidewall portions, and, a fluid operated cylinder means mounted on said support member at a position forwardly of said axis, said cylinder means including a piston having a piston rod connected thereto and extending downwardly toward said table and having means on the free end thereof for bearing against said table, said cylinder thereby mounted for reciprocal movement toward and away from said table upon extension of said piston, thereby causing said guard means to pivot about said axis.

7. The safety device of claim 4 wherein said means on the end of said piston rod comprises a socket connected to said piston rod and a ball mounted for rotation in said socket for bearing against said table.

8. The safety device of claim 4 further comprising: means operable from a location remote from said guard means and mounted thereon for actuating said cylinder means to move said guard means between said first and second positions.

9. The safety device of claim 1 further comprising: an arm means rigidly connected to and extending upwardly from said support member, said arm acting as a stop for pivotal movement of said guard means when said guard means is moved to said third stowed position.

10. The safety device of claim 1 further comprising: stop means attached to the bottom portion of said guard means for limiting the pivotal travel of said guard means downwardly toward said table about said axis thereby fixing the distance at which said guard means rests above said table in said first position.