US2771797A - Drill press - Google Patents

Description

Nov. 27, 1956 B. w. BENBOW 2,771,797

DRILL PRESS Filed May 5, 1952 3 Sheets-Sheet 1 INVENTOR. Buff/'5 W fienbow ATTORNEY! Nov. 27, 1956 B. w; BENBOW 2,77

DRILL PRESS Filed Kay 5, 1952 ,3 Sheets-Sheet 3 PIE E IN V EN TOR.

flurf/s fienbow A TTORNE Y5 DRILL PRESS Burtis W. Benbow, San Leandro, (Iaiif.

Application May 5, 1952, Serial No. 286,115

11 Claims. (131. 77-29) This invention relates generally to drilling apparatus and particularly to machines commonly known as drill presses.

In my Patent 2,483,613 I have disclosed a drill press which incorporates a clutch in such a manner that when the drill is pressed against a work piece, the clutch is automatically engaged to drive the drill. An arrangement of this type is advantageous in that the drill is driven only when it is pressed against the work, thus reducing drill breakage to a minimum and making possible better control of drilling operations.

It is an object of the present invention to provide certain improvements to the drill press disclosed in said Patent 2,483,613.

More particularly it is an object of the present invention to provide an improvement which will enable one to lock the main vertical shaft of the machine head to thereby facilitate operation of the chuck to engage or disengage drills.

Another object of the invention is to provide novel means whereby the clutch can be engaged without the necessity of urging the drill against a work piece.

Another object of the invention is to provide an improved change-speed drive means for a. drill press.

Additional objects and features of the invention will appear from the following description in which the preferred embodiments of the invention have been set forth in detail in conjunction with the accompanying drawing.

Referring to the drawing:

Figure l is a plan view illustrating a drill press incorpo rating the present invention.

Figure 2 is a side elevational view of the drill press shown in Figure 1.

Figure 3 is a plan view like Figure 1 but showing parts in a diiferent operating position.

Figure 4 is an enlarged cross-sectional detail illustrating the clutch and the parts associated with the same.

Figure 5 is an enlarged cross-sectional detail taken along the line 5-5 of Figure 2.

Figure 6 is a cross-sectional detail taken along the line 6-6 of Figure 5, with the parts in a diiferent operating position.

Figure 7 is a side elevational view in section illustrating another embodiment of the invention.

Figure 8 is a plan view of the drill press shown in Figure 7, with certain parts in section.

The drill press illustrated particularly in Figures 1 and 2 of the drawing consists of a vertical standard '10, which is carried by a suitable base (not shown). A head frame 11 is slidably carried by the standard 10, and can be clamped at any desired elevation by turning the clamping lever 12. The head frame 11 carries the driving motor 14, the shaft of which is attached to the multi-diameter sheave 16. A suitable driving belt 17 engages one of the diameters of the sheave 16, and also a cooperating diameter of the sheave 18, the latter forming a part of the head assembly.

Instead of mounting the motor 14 directly upon the 1 2,771,737 Patented Nov. 27, 1956 head frame 11, it is shown secured to a mounting plate 19. This plate is pivotally attached to 21 to the head frame 11, and is also pivotally attached to the link 22.

At the front of the machine there is a guard 23, which normally extends over the front half of the sheave 18, and which is pivotally carried by the bolt or screw 24. An arm 26 is secured to the guard 23, and has its free end pivotally attached to the link 22.

The arrangement described above is such that when the guard 23 is in the normal position illustrated in Figures 1 and 2, the distance between centers of sheaves 16 and 18 is such that the belt 17 is tensioned for normal driving. When guard 23 is swung forwardly and to one side as illustrated in Figure 3, the mounting plate 19 and the motor 14 are swung toward the front of the machine, as illustrated in Figure 3, thus shortening the distance between the centers of sheaves 16 and 18, and causing the belt 17 to be slackened. The slack is suflicient to enable the belt to be shifted to any sheave diameter desired, thus permitting the operator to select a desired speed of operation. After the desired belt position has been selected, the guard 23 is swung back to the position illustrated in Figures 1 and 2, whereby the motor is swung rearwardly to cause the belt 17 to be tightened. It will be noted in Figure 1 that the arm 26 passes dead center position with respect to the link 22, thus retaining the guard in closed position.

Additional parts of the drill head assembly are illustrated in Figures 4, 5 and 6. The sheave 18 is journaled upon a sleeve 28, which is fitted in the portion 29 of the machine frame. The sleeve 28 also forms a bushing through which the shaft 31 extends. The upper portion of shaft 31 is fluted, and has a splined drive with respect to the clutch cone 32. The cone 32 is adapted to have driving engagement with the inner conical surface 33 of the sheave 18.

Another vertical sleeve 34 is slidably fitted within the frame portion 36, and generally embraces the shaft 31. A suitable thrust bearing, such as the ball bearing assembly 37, is interposed between the upper end of the sleeve 34 and the cone 32. A member 38 is fixed to the sleeve 34, and is bored horizontally to provide a iournal for the shaft 39. This shaft has one exterior end attached to the operating handle 41, and also carries a pinion 42. A sleeve 43 is slidably fitted within the sleeve 34, and forms a journal for the lower portion of the shaft 31. One side of the sleeve 43 is formed to provide the gear rack 44, the teeth of which engage the teeth of the pinion 42. The lower end of the shaft 31 carries a chuck 46 which serves to grip a drill or like tool 47.

With the arrangement described above the turning of pinion 42 by swinging the lever 41 serves to raise or lower the sleeve 43, and to likewise raise or lower the shaft 31. If the drill 47 carried by the chuck 46 engages a work piece, downward force applied upon the lever 41 causes the shaft 39 and the pinion 42 to be urged upwardly, together with member 33 and the sleeve 34. The upwardly applied force urges the cone 32 against the inner conical surface 33 of the sheave 18, to establish a driving connection. Thus under such conditions, and assuming that the motor is in operation to drive the sheave 18, torque is applied to the shaft 31 for a drilling operation. When the drill is elevated from contact with the work, driving engagement of the clutch cone 32 with the conical surface 33 is immediately interrupted, whereby the drill automatically stops.

In Figure 4 the drill shaft 31 is shown in its uppermost position. In this position the shaft is locked against rotation. The locking means makes use of a member 48, which is carried by the stationary cap 49. Member 48 is provided with one or more keys which engage within the flutes of shaft 31. Locking of shaft 31 against rotation in 3 its upper limiting position facilitates release of clamping operations of the drill chuck 46.

In certain types of drilling operations it is desirable to engage the clutch without the necessity of urging the drill against the work piece. My drill press incorporates means for this purpose, including the part illustrated in Figures 5 and 6. The member 38 is provided with a side extending portion 51, which overlies a portion 52 that is integral with the frame part 36. Camming means is interposed between the portions 51 and 52, and utilizes the metal ball 53. The upper part of this ball is normally seated in a recess formed in the plug 54. The plug is adjustably threaded in the portion 51. The lower portion of the ball is normally seated in a recess formed in the upper end of a plunger 56. The plunger is slidably fitted within a sleeve 57 which is adjustably threaded in the portion 52. A compression spring 58 normally urges the plunger 56 upwardly against the ball. Downward movement of the plunger 56 against the spring 53 is limited by the upper end 59 of thesleeve 57.

Operation of the parts illustrated in Figures 5 and 6 is as follows: The compression spring normally causes the ball 53 to be clamped within the two accommodating recesses formed in the plug 54 and the plunger 56. Therefore the plug and plunger 54 and 56 are normally maintained in alignment, although the upward thrust of the spring 58 is not sufiicient to force the clutch to engaged position. If the hand lever 41 is swung to the left or to the right, there is a camming action upon ball 53 which serves to increase the vertical distance between the portions 51 and 52, thus raising member 38 together with the sleeve '34 to move the clutch cone 32 to engaged position. Such a camming position is illustrated in Figure 6. Immediately upon release of the lever 4-1, the parts return to the nor mal aligned position illustrated in Figure 5.

Since the lever 41 serves both for the purpose of low ering the drill, and for causing the clutch to be engaged without the necessity of contacting the drill with a work piece, it will be evident that the over-all operation of the drill press is greatly facilitated. The drill press operator may utilize the automatic features of the clutch to control turning of the drill, and at the same time the drill can be started and stopped as desired, independently of contact of the drill with the work piece, and by manipulation of the same operating lever 41.

In the embodiment of the invention illustrated in Figures 7 and 8, the head frame 61 is carried by the standard 10, and is vertically bored to receive the sleeve 62. This sleeve has a gear rack 63 which is engaged by a pinion 64. The sleeve 62 forms a journal for the vertically movable shaft 66, the lower end of which carries the drill chuck 67. A member 68 is bored horizontally to journal the shaft 69, and this shaft serves to mount the pinion '64. One exterior end of this shaft is attached to the operating lever 71. Member 68 is carried by the vertical pin or bolt 72, the upper end of which is attached to the lever 73. The rear end of this lever is pivoted at 74 to the frame 61, and the forward end embraces the shaft 66, and engages a thrust bearing assembly 75, which underlies the clutch cone 76 and sheave '77.

The lower end of member 68 has a rearwardly extending portion 78, which overlies a portion 7 9 which extends from the frame 61. Portions 78 and 79 carry the parts of the'camming means illustrated in Figures 5 and 6, including particularly the cam ball 53.

Thedrill press illustrated in Figures 7 and 8 operates as follows: Assuming that the sheave 77 is being driven, movement of the lever 71 in a vertical direction serves to raise or lower the drill, and when the drill is pressed down against a work piece, member 68 is urged upwardly, thus causing the lever 73 to press upwardly against the thrust bearing 75, to thereby move the clutch cone 76 to engage position. When the lever 71 is swung to the left or to the right, member 63 pivots about the axis of bolt 72, and this causes the ball 53 to exert a camming action to move the portions 78 and 79 apart in a vertical direction. This likewise applies upward force -to the lever 73 to move the clutch cone 76 to engaged position.

it will be evident from the foregoingthat I have provided a drill press having many desirable features. It has the advantages of automatic control of the drill which are disclosed in my Patent 2,483,613, and at the same time the drill can be driven without the necessity of forcing the drill against the workpiccqand by manipulation of the same operating lever which is used for raising or lowering the drill. Movement ofthe shaft -31 to locking position as illustrated in Figure 4 isdesirable in that it greatly facilitates manipulation of the drill clamping chuck. The change speed mechanism facilitates rapid changes in the driving speed for the drill, with a minimum number of operating parts for releasing the belt tension.

1 claim:

1. in a driil press, a frame, a vertical shaft carried by the frame, the lower end of the shaft being adapted for attachment to a drill, a sleeve concentric with the'shaft and through which the shaft extends, said shaft being journaled in said sleeve, a member movable vertically with respect to the frame, a pinion carried by said memher, an operating lever connected to said pinion whereby the pinion is turned when the operating lever is moved in a vertical direction, a gear rack formed on said sleeve and engaging said pinion, drive means for the shaft including sheave concentric with the shaft, friction clutch means adapted to be engaged for causing the sheave to drive the shaft, said friction clutch means including a clutch member concentric with the shaft and movable between engaged and disengaged clutching position responsive to vertical movement of said member, whereby swinging said lever in a vertical direction causes the drill to be lowered against a work piece and to cause said friction clutch means to be engaged to drive the drill when the drill is pressed against the work piece, and camming means acting between said member and said frame and serving to move the member in a vertical direction responsive to swinging said lever in a horizontal direction, whereby such movement of said member causes engageent or disengagement of said friction clutch means independently of pressure between the drill and the work piece.

2. A drill press as in claim 1 in which said member is carried by a sleeve portion which is fitted concentrically about said first named sleeve and is rotatable about the axis of said shaft.

3. In a drill press, a frame, a vertical spindle carried by the frame, the lower end of the spindle being adapted for attachment to a drill, drive means for the shaft, said drive means includinga multi-diameter sheave disposed concentric to said shaft and another driving sheave spaced rearwardly from said first named sheave, the sheaves being connected by a driving belt, a sheave guard pivotally carried by the frame for swinging movement between out-of-the-way and guard positions relative to the first named sheave, and means responsive to swinging movement of said guard for moving said second named sheave toward and away from the first sheave.

4. A drill press as in claim 3 in which said second sheave is attached to the shaft of an electric driving motor, and in which the driving motor is carried by a mounting plate, the mounting plate being pivotally attached to the frame to enable movement toward and away from the first named sheave.

5. In a drill press, a frame, a vertical shaft carried by the frame, the lower end of the shaft being adapted for attachment to a drill, a sleeve concentric with the shaft and through which the shaft extends, said shaft being journalled in said sleeve, another sleeve concentric with said first named sleeve and slidably and rotatably mounted thereon so as to be vertically and rotatably movable with respect to the frame and said first named sleeve, a member fixed to said last named sleeve, :1 pinion carried by said member, an operating lever connected to said pin-ion whereby upon rotation of the operating handle in a vertical plane the pinion is rotated, a gear rack formed on said first named sleeve and engaging said pinion, drive means for the shaft including a sheave concentric with the shaft, friction clutch means adapted to be engaged for causing the sheave to drive the shaft, said friction clutch including a clutch member concentric with the shaft and movable between engaged and disengaged clutching positions responsive to the vertical movement of said second named sleeve, whereby rotation of said lever downwardly in a vertical plane causes the drill to be lowered against a work piece and to cause said friction clutch means to be engaged to drive the drill when the drill is pressed against the work piece, and camming mean-s acting between said member and said frame serving to move the member in a vertical direction responsive to rotation of the member about a vertical axis, said member being rotated about its vertical axis by swinging said lever in a horizontal direction whereby such movement of said member causes engagement or disengagement of said friction clutch means independently of pressure between the drill and the work piece.

6. A drill press as in claim 5 wherein the camrning means includes a ball bearing and means mounted in the frame for urging said ball bearing upwardly against said member, the upward force on said ball bearing being insufficient to cause engagement of said clutching means.

7. A drill press as in claim 5 together with means for engaging the upper portion of the shaft, said means serving to lock the shaft against rotation when the shaft is raised to its upper limiting position.

8. A drill press, a frame, a vertical spindle or shaft carried by the frame, the lower end of the shaft being adapted for attachment to a drill, the upper portion of the shaft being fluted, means for raising and lowering the shaft, drive means for the shaft, friction clutch means automatically engaged to cause the drive means to turn the shaft responsive to pressing a drill against the work piece, and key means engaging the upper fluted portion of the shaft serving to lock the shaft against rotation when the shaft is raised to its upper limiting position.

9. In a drill press, a frame, a shaft carried by the frame, one end of the shaft being adapted for attachment to a drill, means for driving the shaft, clutch means for engaging or disengaging the drive means with respect to the shaft, means including an operating lever for raising or lowering the shaft with respect to a work piece, means for causing said clutch means to be engaged responsive to pressing the drill against a work piece by movement 'of the operating lever in one plane, and means operated by movement of said operating lever in a different plane for engaging said clutch means independently of the means for causing the clutch means to be engaged responsive to pressing the drill against the work piece.

10. A drill press as in claim 1 together with a lever having one end pivotally connected to said frame, the lever being movable in a vertical direction to effect engagement or disengagement of said friction clutch means and in which said member is pivotally connected to said lever and is moved in a vertical direction as said member is moved.

11. In a drill press, a frame, a vertical spindle or shaft carried by the frame, the lower end of the shaft being adapted for attachment to a drill and the upper end of the shaft having flutes, means for raising and lowering the shaft, drive means for the shaft, friction clutch means automatically engaged to cause the drive means to turn the shaft responsive to pressing the drill against a work piece, and means for engaging the upper portion of the shaft serving to lock the shaft against rotation when the shaft is raised to its upper limiting position, said last named means comprising a cap mounted on said frame and adapted to receive the upper end of the shaft, and a keyed member mounted in said cap and adapted to engage the fluted portion of said shaft to lock said shaft against rotation.

References Cited in the file of this patent UNITED STATES PATENTS 542,695 Stover et a1. July 16, 1895 595,850 Flickinger Dec. 21, 1897 663,055 Weinman Dec. 4, 1900 1,437,570 Vaughn Dec. 5, 1922 2,063,101 Johnson Dec. 8, 1936 2,089,363 Haas Aug. 10, 1937 2,483,613 Benbow Oct. 4, 1949 2,557,330 Wilger June 19, 1951

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