US3056242A - Polishing tool - Google Patents

Description

sembly 26 between the clearance position and finishing position provides a means of determining the amount of wear of the honing tool and when a dressing thereof is necessary to maintain its dimensional configuration and tfinishing efliciency. The length of reciprocating travel is also directly indicative of the center distance between the honing tool and workpiece. Since the projected or finishing position of the toolhead assembly is determined by the position at which a predetermined pressure exists between the honing tool and the work gear disposed in tight meshing relationship, the gradual wear of the honing tool during use will cause the toolhead assembly to move further outwardly to achieve that pressure causing a greater travel of the toolhead assembly between the finishing position and clearance position, or in other words, the wear of the honing tool causes a progressive decrease in the center distance between the work gear and honing tool. In accordance with the practice of the present invention, the increased stroke of the toolhead assembly, or the decrease in the center distance between the honing tool and work gear, is communicated automatically to the control system of the finishing machine which is conveniently contained in a control cabinet 79 mounted at the right end of the machine (FIG. 1) causing a predetermined dressing of the honing tool and concurrently advancing the toolhead assembly to a new clearance position disposed closer to the work gear.

The honing tool which is of a gear-like configuration and is employed for finishing the tooth elements on the work gear disposed in meshing relationship therewith is comprised of a plurality of tooth elements conjugate to the form of the tooth elements on the workpiece. The honing tools conventionally employed are of the socalled resinoid bonded type wherein a desired quantity of a variety of conventional abrasive grains or mixtures thereof having the appropriate grit size and hardness are imbedded in a synthetic resinous material providing therewith the desired abrasive finishing or honing action and the desired degree of smoothness of the finished surface. The abrasive action between the honing tool and the tooth elements on the workpiece automatically maintains the appropriate profile of the abrasive tooth elements on the honing tool. However, the thickness of the tooth elements on the honing tool decreases during use and the root or bottom of the honing tool along the clearance circle of the honing tool is decreased as a result of a gumming-out of this area by the tips of the tooth elements on the workpiece causing a corresponding decrease in the pitch circle of the honing tool. Accordingly, by dressing the outside diameter of the honing tool in accordance with the practice of the present invention, the appropriate pitch-circle relationship and tooth thickness of the honing tool is restored and eificient abrasive action is maintained between the work gear and honing tool.

Communication of the decrease in the center distance between the honing tool and the work gear as occasioned by the progressive wear of the honing tool is achieved in accordance with one exemplary embodiment of this invention as illustrated in the drawings by means of a disk or plate 80 affixed to the projecting end of the lead screw 48 adjacent to the hand wheel 54 which is adapted to trip a sensing device, such as a limit switch 82, adjustably aifixed to the supporting housing 58 at such time when a predetermined reduction in the center distance occurs and which, upon being tripped, signals the control circuit of the finishing machine so as to cause concurrent advancement of the toolhead assembly and dressing of the honing tool.

Advancement of the toolhead assembly in response to actuation of the sensing device 82 by the disk 80 is achieved through a ratchet mechanism as may be best seen in FIGS. 4 and 5, comprising a rotary ratchet wheel 84 which is splined to the lead screw 48 and axially slidable relative thereto. The ratchet wheel 84 and lead screw to which it is aifixed is rotated at predetermined increment by means of a ratchet pawl 86 pivotally connected to a slide member 88 slidably disposed in a cylindr'ical housing 98 which forms an integral part of the supporting housing 58. The slide member 88 and ratchet pawl 86 thereon is reciprocablle in a direction transversely of the axis of the lead screw to and from an advanced position and a retracted position.

Movement of the slide member 88 from a retracted position as shown in FIG. 5 to the advanced position is achieved by a fluid actuated cylinder 92 having a piston rod 94 thereof disposed in adjustable threaded engagement with the slide member 88. During the advancing movement of the slide member 88, the engaging tooth 96 on the ratchet pawl 86 engages a ratchet tooth 98 on the ratchet wheel 84 causing the ratchet wheel and lead screw to concurrently rotate through a predetermined arcuate movement. Movement of the slide member 88 from the projected position to the retracted position can be achieved by the cylinder 92, or in the case of a single acting cylinder as shown in FIG. 5, by means of a helical compression spring 180- having one end thereof seated against the end of the slide member 88 and the other end thereof against a head portion 102 of the cylindrical housing 90.

The maximum reciprocating movement of the slide member 88 to achieve the desired incremental rotation of a ratchet wheel 84 is adjustably regulated by a stop screw 104 threadably engaged in the head portion 102 and axially disposed within the compression spring 100. The shank end portion of the stop screw 104 is adapted to abut the end of the slide member 88 when the fully projected position is attained.

To assure positive engagement of the engaging tooth 96 on the ratchet pawl 86 and a ratchet tooth 98 on the ratchet wheel 84, a suitable compression spring 106 is employed for biasing the ratchet pawl in a clockwise direction as viewed in FIG. 5 and in firm engaging relationship with the periphery of the ratchet wheel 84 during the advancing movement of the slide member. When in the fully retracted position, the ratchet tooth 96 is withdrawn out of engagement with the ratchet teeth 98 on the ratchet wheel. Inadvertent drift of the lead screw is prevented by a resiliently biased brake 107 disposed in frictional contact against the face of the ratchet wheel 84.

The length of the advancing stroke of the slide member 88 is adjustable and depends on such related factors as the radius of the ratchet wheel 84, the pitch or lead of the threads on the threaded shank portion 50 on the lead screw 48, and the advancing increment through which it is desired to advance the toolhead assembly 26 toward the table 12. As a typical example, the ratchet assembly can be so arranged to cause an advancement of the toolhead assembly in an amount of 0.001 inch each time the sensing device 82 is tripped by the disk 80. Concurrently, the honing tool is also dressed an appropriate amount.

By virtue of the ratchet advancement of the lead screw 48 and a corresponding adjusted decrease in the center distance between the honing tool and work gear, the reciprocating travel of the tool-head assembly and lead screw threadably engaged thereto between the clearance position and finishing position is incrementally decreased whereby the disk is moved to the left as viewed in FIG. 4 and out of contact with the sensing device 82 when the toolhead assembly is in the finishing position. As further wear of the honing tool occurs, the clearance between the disk 88 and the sensing device 82 progressively decreases until the sensing device is again actuated causing another incremental advancement of the toolhead assembly by the incremental rotation of the lead screw.

It will be appreciated by those skilled in the art that satisfactory operation of the ratchet mechanism can also be achieved by a solenoid, for example, or an engageable and disengageable motor driven worm drive assem- 3,056,242 POLISHING TOOL Ernest W. Hunter, 24264 Ocean Ave., Torrance, Calif. Filed June 13, 1960, Ser. No. 35,777 1 Claim. (Cl. 51187) This invention has to do with attachments for power equipment and more particularly with a grinder or sander that is adapted for use with a hand drill.

Heretofore, grinding and polishing devices that were adapted for use with hand drills and motors were incapable of performing, successfully, a number of operations. For instance, the grinding device was of rigid construction which resulted in limiting the operation of the device to the grinding or polishing of relatively fiat or slightly contoured surfaces. Relatively deep narrow grooves and depressions could not be ground or polished. Also, very small contoured object's could not be ground or polished due to the rigid grinding surface which could not adapt itself to the subject contour. Also, there was always the danger associated with a rigid polishing or grinding device that undesirable gouging and routing would occur as a result of undue pressure being exerted. Further, certain of the grinding and polishing devices heretofore in use were, once used, no longer usable.

An object of this invention is to provide a grinder and/or polisher that is adaptable for use with a hand operated power tool or motor.

Another object of this invention is to provide a grinder or polisher device that has a resilient component included therewith that enables the device to conform to the contour of the surface to be ground or polished.

A yet further object of this invention is to provide a grinder or polisher that, by virtue of its construction, may grind or polish areas that include relatively deep, narrow depressions and/ or grooves.

A still further object of this invention is to provide a grinder or polisher device that will not gouge, route or otherwise undesirably score the material surface to which the device is applied.

Another object of this invention is to provide a grinder or polisher that may be readily used by the unskilled, is economical to fabricate of nonessential materials, and is subject to mass production methods and techniques.

Briefly the invention comprises a shaft, threadably attached to a rigid wafer of plastic material. A soft rubber member is adhesively affixed to said wafer, and wrapped about the member and wafer and clamped thereon is an emery, sanding, or polishing strip of material.

FIGURE 1 is a fragmentary, perspective view illustrating and having embodied therein the present invention.

FIGURE 2 is a fragmentary, longitudinal cross-sectional view of the invention.

Referring to the drawings for a more detailed description of the present invention 10 designates a hand operated drill or motor on which is the conventional chuck 12.

An elongated shaft 14 is, under the normal operating conditions, firmly inserted into the chuck. That end 16 of the shaft 14, in opposed relationship to that end inserted in the chuck, is threadably inserted into an epoxy resin wafer 18.

The contour of the wafer 18 is circular with a boss 20 tates Patent ice depending or extending therefrom which results in providing an annular flange 22.

The shaft 14 is centrally located in the wafer and, as may be determined by referring to FIGURE 2, extends into the boss 20.

A soft, sponge-like, rubber member 24, having a cylindrical configuration, is adhesively alfixed to the epoxy resin water. An opening, centrally located in the member 24, receives the boss 20 of the wafer 18. The circumference of the member 24 is the same as the circumference of the wafer, or to phrase it another way, both the member and wafer have the same diameter.

An elongated strip of emery cloth, sandpaper, or polishing material 26 is wrapped about a portion of the member 24 and wafer 18. The free ends of the material 26 are clamped between a pair of washers 28 and 3t Washer 28 is slidable on shaft 14, as is washer 30, but the former is in contacting relationship with wafer 18.

Also threaded on shaft 14, between the chuck 12 and washer 30, is a butterfly nut 32. The butterfly nut may be threaded down on the shaft 14, away from the chuck 12, to provide a clamping action to the washers 28 and 30 in order to firmly retain the emery cloth or material 26 in place.

The operation of the device is as follows: The material 26 is wrapped about the member 24 and wafer 18 and clamped into place between washers 28 and 30, through the medium of nut 32. It will be seen, by referring to the drawing, that in the assembled relation of the tool the material 26 completely covers the lower end of the member 24 and contacts diametrically opposed portions of its cylindrical surface. It will also be seen, by referring to FIGURE 2, that the area of the cylindrical surface of the member 24 exceeds the area of one of its ends. The shaft 14 is inserted into the chuck 12 and the motor 10 is caused to operate or rotate. It may be seen that the material 26 may be placed into contact with a material to be ground or polished but because of the rubber disc 24 no undesirable gouging, routing, or scoring will occur for the reason that excessive pressure will cause the disc 24 to distort, relieving the pressure, in those exposed areas each side of the material 26. Also, if the material to be ground or polished is small and has severe contours or is large and has severe contours the member 24 will assume the contour thereof. Further, in the event a relatively narrow, deep groove or depression needs polishing or grinding, an edge of the member 24, with material 26 thereon, is inserted therein. The disc again distorts to assume the contour of the depression which results in there being a grinding or polishing of the bottom of the depression as well as the sides.

Additionally, instead of the material 26 being wrapped in the manner shown and described, a member having the same diameter as member 24 may be applied to the bottom of the latter. A pressure sensitive adhesive may be applied to either the disc 24 or to the disc of material.

While, in order to comply with the statute, the invention has been described in language more or less specific as to structural features, it is to be understood that the invention is not limited to the specific features shown, but that the means and construction herein disclosed comprise a preferred form of putting the invention into effect, and the invention is therefore claimed in any frame for restricting rearward movement of said toolhead beyond the adjusted said clearance position, sensing means and actuator means associated with said frame and said screw means disposed in variable spaced relationship and relatively movable in relationship to the movement of the said toolhead relative to the workpiece, said actuator means operable to trip said sensing means on a predetermined incremental increase in the travel distance of said toolhead between said clearance and said finishing position caused by the wear of said tool, dresser means actuable in response to said sensing means for dressing the periphery of said tool and causing an incremental reduction in the diameter thereof, and compensating means associated with said screw means for advancing said clearance position of said toolhead toward the workpiece an increment corresponding substantially to the increment removed from the periphery of said tool by the dressing thereof.

10. In a tool dresser mechanism for an abrasive machine for finishing tooth elements; the combination comprising a frame including means for rotatably mounting a toothed workpiece thereon, a toolhead on said frame including a gear-shaped abrasive honing tool rotatably and drivingly mounted thereon, said toolhead movable laterally of the axis of rotation of the workpiece to and from a clearance position wherein said tool is disposed in spaced relationship from the workpiece and a finishing position wherein said tool is disposed in tight meshing relationship with a workpiece, urging means for biasing the toolhead and said tool thereon toward said finishing position, retracting means for retracting said toolhead to said clearance position, adjusting means coacting with said toolhead for adjusting said clearance position thereof and including screw means slidably mounted on said frame and threadably engaged in said tooihead, and stop means associated with said screw means and said frame for restricting rearward movement of said toolhead be yond the adjusted said clearance position, sensing means and actuator means associated with said frame and said screw means disposed in variable spaced relationship and relatively movable in relationship to the movement of the said toolhead relative to the workpiece, said actuator means operable to trip said sensing means on a predetermined incremental increase in the travel distance of said toolhead between said clearance and said finishing position caused by the wear of said tool, dresser means actuable in response to said sensing means for dressing the periphery of said tool and causing an incremental reduction in the diameter thereof, and compensating means associated with said screw means for advancing said clearance position of said toolhead toward the workpiece an increment corresponding substantially to the increment removed from the periphery of said tool by the dressing thereof, said compensating means comprising ratchet means for rotating said screw means through a predetermined arcuate movement and advancing said clearance position of said toolhead a predetermined increment toward the workpiece.

11. In a tool dresser mechanism for an abrasive machine for finishing tooth elements; the combination comprising a frame including means for rotatably mounting a toothed workpiece thereon, a toolhead on said frame including a gear-shaped abrasive honing tool rotatably and drivingly mounted thereon, said toolhead movable laterally of the axis of rotation of the workpiece to and from a clearance position wherein said tool is disposed in spaced relationship from the workpiece and a finishing position wherein said tool is disposed in tight meshing relationship with a workpiece, means for moving said toolhead between said clearance position and said finishing position, adjusting means for positioning said toolhead in said clearance position, presettable means for sensing a predetermined incremental increase in the travel distance of said toolhead between said clearance and said finishing positions caused by the wear of said tool, a dresser head including cutter means disposed adjacent to said tool and including first ratchet means thereon actuable in response to said presettable means for advancing said cutter means toward said tool causing an incremental reduction in the diameter thereof, and compensating means associated with said adjusting means including second ratchet means actuable in response to said presettable means for advancing the clearance position of said toolhead toward the workpiece an increment corresponding substantially to the increment removed from the periphery of said tool by the dressing thereof.

References Cited in the file of this patent UNITED STATES PATENTS 1,183,020 Maag May 16, 1916 2,627,141 Praeg Feb. 3, 1953 2,942,389 Praeg et al. June 28, 1960

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