US 3123156 A
Description (OCR text may contain errors)
March 3, 1964 J. J. GAPSTUR 3,123,155
ROTARY AND PERCUSSIVE TOOL Filed April 16, 1959 \l I l FIG. 2
INVENTOR. JOHN J. GAPSTUR ATTORNEYS Unite states 3,123,155 RGTARY AND PERCUSSTVE T891 John 5. Gapstnr, Cleveland, fihio, assignor, by mesne assignments, to Rubbermaid incorporated, Wooster, @hio, a corporation of Shin Filed Apr. 16, 195?, Ser. No. 3%,917 2 Claims. (Ql. 173- 58 This invention pertains to rotary percussive tools and more particularly to a tool for selective use either as an ordinary crill, or as an impact drill.
in this past, several proposals have been made for rotary and percussive tools in which a drill bit is driven by a constantly rotatable shaft and in which repetitive percussive impacts may, when desired, be provided while the bit is rotating. These prior proposals have resulted in mechanisms wherein considerable strain has been placed on the bearings of the drive motor, and in which considerable vibration has been transmitted to the hands of the operator. In addition, sliding and wearing surfaces have been present whi h minimize the life of the device. Further, the sliding and wearing surfaces minimize the efficiency of the device by absorbing a substantial portion of the motivating power. The present invention overcomes these and other disadvantages of prior mechanisms.
Accordingly, one of the principal objects of the invention is to provide a novel and improved rotary and percussive device in which the shaft rotates constantly whether the device is used for ordinary drilling or impact drilling.
A related object of the invention is to provide a novel and improved rotary and impact tool in which all relatively moving surfaces are bee-ringed.
Another principal object of the invention is to provide a novel and improved rotary impact tool in which a constantly rotatable impact delivering shaft is operably connected to a drive means through a connection which will transmit substantially no axial thrust, and in which the impact delivering shaft includes thrust absorbing means thereby protecting the bearings of the motor and minimizin'g the vibration imposed on the operator.
Another object of the invention is to provide a novel and improved rotary percussive tool in which an anvil rotates with a shaft relative to a housing, and in which a selective mechanism is provided to selectively cause the anvil to reciprocate while it rotates.
A related and more special object of the invention is to provide an anvil rotatable with a shaft and a housing, in which the anvil has a peripheral cam groove, and in which a cam follower roller is carried by the housing and selectively movable radially into and out of the cam groove.
Anot er object of the invention is to provide a novel and improved rotary and percussive tool made in accordance with the foregoing objectives in which a drill bit holding chuck is provided, and in which the chuck is an integral part of the unit.
A related and more special object of the invention is to provide a novel and improved chuck for transmitting rotative and impact forces from a rotating shaft to a drill bit, which chuck is simple and inexpensive to make and free from susceptibility to either slipping or jamming.
Other objects and a fuller understanding of the invention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawings, in which:
FTGURE 1 is a fragmentary side elevational view of the novel and improved rotary and percussive tool witparts broken away and removed to show the impact delivering assembly in section; and,
FTGURE 2 is a side elevational view of the novel and improved anvil of the device.
Referring to the drawings, a rotary percussive tool is shown which has a motor cage T3. A motor is housed in the cage i s; a fragmentary section of an armature for the motor is shown at 11. The motor cage may be shaped in the form of the well known pistol grip type hand drill with a trigger 12 provided to actuate the rotary and percussive device. The motor has a shaft 13 which imparts a rotary force from the motor through a gear train 14 to the object being driven. A hous ng 15 is connected to the cage it) as by screws 16' only one of which is shown.
A shaft 17 is journaled in the housing 15 and operably connected to the motor shaft 13. The shaft 17 includes an enlarged chuck end portion or anvil which is journaled in a roller bearing in. The shaft also includes a reduced diameter portion 19 which may be threaded into the enlarged portion 15 at 259.
The shaft 27 includes a drive head 21 at the end opposite the enlarged portion 1?. The drive head 21 has a hexagonal aperture 22 which receives a hexagonal drive nut .23 to form a part of the operative connection betwee the shaft 17 and the motor shaft 13. The drive nut 23 and the aperture 22 form a connection which is longitudinally slidable to prevent impact forces from being transmit ed to the gear train 14 and motor bearings, not shown. The shaft head 21 is journal-ed in a second roller bearing 24. The roller bearings 16, 24 are frictionally or otherwise suitably held by the housing 15.
An end cap is threaded onto one end of the housing 15. The cap 2 5 axially locates a suitable dust and oil seal 26. The end cap 25' also carries a suitable thrust bearing 2%. The thrust bearing 2 engages a radially extending shaft shoulder 29 to receive the end thrust of the shaft 17. The slide connection between the hexagonal drive nut 23 and the aperture 22 provide one of the outstanding advantages of the invention. Substantially no axial thrust is transmitted to the gear train 14.
A suitable masonry drill bit 343 may be positioned in a chucking arrangement provided at outer end 31 of the shaft 17. The chucking arrangement provides one of the outstanding advantages of the invention. in this arrangement the bit 39 projects into a bottomed bore 41 which extends axially from the outer end 31 into the body of the enlarged or end portion 13 of the shaft 37.
Rotative force is transmitted from the shaft 17 to the drill 3% by one or more hard shaft flats in the form of dowel pins 32. In the preferred and disclosed arrangement a pair of dowel pins are provided which partially project into the bore 41 and are within the geometric contour of the bore. The pins 32 engage a pair of hats 33 formed adjacent the end of the drill bit 3%. It will be seen that the dowel pins 32 are provided as a convenient, simple technique for providing hard, flat transversely extending surfaces to engage the bit flats 33. The dowel pins 32 also tend to provide guide surfaces to locate the rill bit 3% axially when it is inserted in the bore .1.
The inner end of the bit abuts a disc 42. A backup pad $3 is interposed between the disc 42 and the bottom of the bore 41. The disc and pad protect the shaft from damage from impact exerted on the bit when the device is in operation.
The bore 41 includes a tapered preferably frustoconical shaped section 35 adjacent the end 31 of the shaft 17. The frusto-conical shaped section 35 receives a split chucking ring 35. The split ring 36 has its largest girth intermediate the ends and a tapered surface preferably in the form of a truncated cone 37 which is complemental to the surface of the section 35. A split ring tightening nut or collar 38 is threaded onto the end 31 3 of the shaft 17. The ring tightening collar 38 has a through bore with an inner tapered and preferably truncated section 39. The surface of the collar section 3? is complemental to a second tapered and preferably frustoconical shaped surface 4% on the split ring 36. It will be seen that as the chuck tightening collar is tighten onto the shaft 31 the coaction of the complemental frustoconical surfaces 35, 37 and the complemental frustoconical shaped surfaces 39, 40 will tighten the split ring 56 down against the drill bit 39 to stabilize it and hold it in a desired position. The hammering action of a drilling operation will drive the drill bit 3% in against the bore end disc 42 and pad 43 if any space is left therebetween when a bit is chucked.
A rotatable and reciprocal hammer 45 is provided. The hammer E5 is telescoped over the shaft and reduced diameter portion 19. A pair of flats .6 are provided on the reduced diameter portion 19 to engage complemental flats on the hammer 45 and cause the hammer to rotate with the shaft 17. The shaft complemental hats are longer than the hammer flats to permit relative reciprocation of the hammer on the shaft.
In FI URE 1 the hammer 45 is shown in engagement with an impact receiving end surface 48 on the inner end of the enlarged portion or anvil 2-5 of the shaft E7. The hammer 45 is urged towards the surface 48 by a spring 49. The spring 49 has one end positioned against a shoulder 5t which is preferably formed in a counter bore in the hammer 45. The spring also engages the shaft head 21. The spring is held in compression bet ween the shoulder 50 and the shaft head 21. The spring rotates with the shaft and the hammer as.
in the preferred and disclosed arrangement a hammer guide sleeve 5 is carried in the housing 15. The hammer guide sleeve serves as a sleeve bearing for the hammer 25. The guide sleeve 51 also serves as a convenient means of providing a positioning shoulder 52. A thrust and positioning washer 53 is interposed between the shaft head 21 and the shoulder 52 to give axial location to the entire rotating asset rbly.
A cam groove 55 is formed in the peripheral surface of the hammer 45. The groove is at least partially circumferential of the shaft axis and it is preferably, as disclosed, an annular groove concentrically disposed about the shaft axis. The cam groove 55 has a rear side wall 56 which forms a cam surface. The cam groove 55 has a front side wall 57 which may be shaped to serve as a guide surface. A cam follower in the form of a roller is selectively positionable in the cam groove 55. The roller coacts with the cam surface 55 to shift the hammer against the urging of the spring and impart reciprocal motion to the hammer 45.
Fr/hen the hammer 4-5 is rotated the roller coacts with an inclined section 51 of the cam surfaces 56 to shift the hammer 45 away from the enlarged part 18 of the shaft. As the roller 6i? passes a high spot 62 on the cam surface 55 the spring will urge the hammer 45 forward to strike the enlarged part of the shaft with a hammer blow.
As the hammer continues to rotate after the roller has passed over the high spot, the cycle will be repeated and, in the embodiment shown one impact per revolution will be delivered. To assure proper coaction of the roller 6% and the high spot 62, the guide surface 57 includes an inclined section 53 to urge the hammer 45 back against the enlarged part 18 before the next hammering cycle commences. The coaction of the roller 60, the incline portion 63, and the spring 49 assure positioning of the hammer in the position shown in FIGURE 1 before another hammering cycle is commenced. Thereafter, on continued rotation the incline 61 will again coact with the roller 68 to urge the hammer away from the impact surface 43 on the enlarged portion 18.
Another of the advantages of this invention is that one may obtain either ordinary rotary motion or the previously described rotary impact motion with constant rotation. If one wishes to obtain ordinary rotary motion, this is accomplished by withdrawing the roller 69 from the groove 55. An adjustment stem 65 is provided to carry the roller 66. The adjustment stem 65 has a threaded portion 66 which receives an adjustment knob 67. A stop '72 is provided to kee the adjustment knob 67 from being accidentally threaded off of the adjustment stem 65.
A retaining block 58 is connected to and forms a part of the housing 15. As the adjustment or selector knob 67 is tightened, it works against the retaining plug 58 to draw the adjustment stem 65 outwardly against the action of a selector spring 69. The selector spring 69 is carried in a bore 7a) in the plug 68. The selector spring 6% is positioned between the plug 68 and a shoulder 71 on the adjustment stem 65 to urge the stem inwardly along a path which is radial with respect to the drive shaft 17 After an ordinary drilling operation has been completed, the tool may be returned to the rotary impact position by the simple expedient of loosening adjustment knob 6'7 and then causing the hammer to reciprocate. When the roller comes into alignment with the cam groove 55, the selector spring 69 will urge the adjustment stem 65 inwardly and snap the roller 6i) into the cam groove 55.
Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.
What is claimed is:
1. A percussive tool assembly, comprising a housing, a sha;t constructed to be rotatably driven about its longitudinal axis by a driving motor for rotatably driving a tool in said assembly, a hammer telescopically surrounding said shaft and mo /ably mounted in said housing and having a non-rotational connection with said shaft ermitting movement of said hammer axially of said shaft and adapted to be rotatably driven by said shaft,
means responsive to rotation of said hammer reciprocating said hammer axially relative to said shaft to transmit impact blows to said tool; said means including a cam recess on the periphery of said hammer formed to coact with an axially fixed member to move said hammer away from said tool and then release it, spring means urging said hammer toward said tool, an axially fixed member carried by said housing and radially movable relative to said housing into and out of said recess between hammer reciprocating position and hammer non-reciprocatin position, a coil spring urging said member radiall inwardly during rotation of said hammer by said shaft into engagement with said recess in said harnmer reciprocating position, and means for holding said member out of said recess.
2. A percussive tool assembly, comprising a housing, a shaft constructed to be rotatably driven about its longitudinal axis by a driving motor for rotatably driving a tool in said assembly, a hammer telescopically surrounding said shaft and movably mounted in said housand having a non-rotational connection with said shaft permitting movement of said hammer axially of said shaft adapted to be rotatably driven by said shaft, means responsive to rotation of aid hammer for reciprocating said hammer axially relative to said shaft to transmit impact blows to said tool; said means including a cam recess on the periphery of said hammer formed with a groove circumfcrentially inclined to coact with an axially fixed member to lift said hammer away from said tool and said incline groove havinga sharp shoulder effective to release said hammer at its highest point of lift, spring means urging said hammer toward said tool whereby to provide an impact blow of said hammer on said tool when said hammer is released at said shoulder, an a7ia11y fixed member carried by said housing and radially movable reiative to said housing into and out of said recess beiween hammer reciprocating position and hammer non-reciprocating position respec'iively, and means for holding said member in or out of said References fired in the file of this patent UNITED STATES PATENTS Bodrigues June 18, 1912 Olson Mar. 14, Jones Sept. 11, Kollerk Oct. 14, Jones Apr. 19, Richards June 20, Morris Aug. 18, Mossberg Aug. 18, Bugg July 6, Bachrnan Dec. 25, Chiitenden Dec. 11, Maui-er Mar. 12, Beeson June 4, Muthmann June 28, Oros Aug. 2,