Patent Application
20120048586
1. Field of the Invention
The present invention is generally related to power equipment, and more specifically is related to drill presses having noise reducing components.
2. Description of the Related Art
Drill presses typically include a base, a vertical support column extending upwardly from the base, a table attached to a mid-section of the vertical support column for holding work pieces, and a head stock secured to an upper end of the vertical support column. The head stock includes a rotatable handle that is turned for moving a spindle up and down along a vertical axis that is parallel with the longitudinal axis of the vertical support column. The height of the table may be adjusted using a second rotatable handle coupled with a rack and pinion system. The table may be rotated about the longitudinal axis of the support column to offset the table from the vertical axis of the spindle. In some designs, a drill chuck for holding a drill bit is connected to a lower end of the spindle. The drill chuck may have three jaws that hold an upper end of the drill bit in the chuck. Some drill presses include a spindle having a lower end with a tapered opening for receiving a drill bit having a tapered shaft that fits into the tapered opening. When the drill press is activated, a motor rotates pulleys via one or more drive belts, which, in turn, rotate the spindle and the drill bit secured to the lower end of the spindle.
Drill presses provide many advantages over hand-held drills. First, the spindle is moved up and down along a vertical axis by a rotatable handle coupled with a rack and pinion system, which provides an operator with considerable mechanical advantage. Thus, less effort is required to advance the drill bit through a work piece. Second, a drill press has a table for supporting a work piece, which enables a vice grip or clamp to be used to hold the work piece in an immoveable position on the table. In addition, the spindle moves along a fixed vertical axis relative to the top surface of the table, which allows operators to accurately drill holes in work pieces.
Many drill presses have a mechanism for changing the speed of rotation of the drill. Often, the speed is changed by manually moving one or more drive belts across a stepped pulley arrangement. In one conventional design, in order to change the speed, an operator must first move the motor to provide sufficient slack in at least one of the drive belts. After the drive belts are repositioned, the motor is moved back to its initial position for tensioning the drive belts. Moving the motor requires that the motor be mounted in such a way that it may be translated to allow for belt tensioning. This mounting arrangement may cause unwanted noise and vibration if the machining of the drill press is not precise. Recently, some drill presses have added a third stepped pulley to increase the range of speeds. Some drill presses are equipped with a variable speed motor or a continuously variable transmission, which enable operators to change speeds while the machine is running.
In conventional drill presses, there is excessive clearance between the larger diameter opening at the sleeve upper end 26 and the spindle outer surface. As a result, when the drill press is operated with the spindle 30 in the retracted position shown in
In view of the above deficiencies, there is a need for drill presses that have noise reducing components, and which are quieter when being operated.
In one embodiment, a drill press having noise reducing components desirably includes a spindle pulley having a central opening extending along an axis, the spindle pulley being rotatable about the axis, and a sleeve disposed within the pulley central opening, the sleeve having a central opening aligned with the pulley central opening and the axis. The drill press preferably includes a locking nut connecting an upper end of the sleeve with the spindle pulley for supporting simultaneous rotation of the sleeve and the spindle pulley. A spindle is desirably disposed within the sleeve central opening of the sleeve and extends along the axis, whereby the spindle is slidable along the axis relative to the sleeve and is rotatable with the sleeve about the axis. The drill press desirably includes a spacer disposed between the spindle and the locking nut for aligning the spindle with the axis and for preventing the spindle from contacting the sleeve upper end during rotation of the spindle and the sleeve about the axis.
In one embodiment, the sleeve has the upper end, a lower end, and the sleeve central opening extends between the upper and lower ends of the sleeve. The sleeve central opening preferably has a larger diameter section adjacent the sleeve upper end and a smaller diameter section adjacent the sleeve lower end.
In one embodiment, the spindle preferably has an elongated spindle shaft with a length aligned with and extending along the axis. The spindle desirably includes splines that extend along the length of the elongated spindle shaft. The splines are desirably adapted to mesh with the smaller diameter section at the sleeve lower end for transmitting rotation forces from the sleeve to the spindle shaft. In one embodiment, the sleeve smaller diameter section has a plurality of protrusions adapted to mesh with the spindle shaft splines for transmitting rotational forces from the sleeve to the spindle shaft. The splines desirably define an outer diameter of the spindle shaft that is smaller than the sleeve larger diameter section.
In one embodiment, the sleeve upper end desirably has external threads adapted to mesh with internal threads on the locking nut. The locking nut preferably has a central aperture aligned with the axis, and the spindle is slidable along the axis relative to the locking nut. In one embodiment, the spacer is ring-shaped (e.g. shaped like a grommet) and is secureable within the locking nut central aperture. The spacer desirably has a central aperture aligned with the axis, whereby the spindle is adapted to slide along the axis relative to the spacer.
In one embodiment, the locking nut has an annular projection that extends into the locking nut central aperture and the ring-shaped spacer has an outer surface including an annular groove that is adapted to receive the locking nut annular projection. In one embodiment, the spacer is desirably made of a non-metallic material such as rubber, polymers, and elastic materials, and the locking nut may be made of metal such as steel.
In one embodiment, a drill press having at least one noise reducing component includes a spindle pulley having an axis and a central opening extending along the axis, a sleeve disposed within the pulley central opening, the sleeve having a central opening aligned with the axis, and an elongated spindle disposed within the sleeve central opening and being aligned with the axis, the elongated spindle being adapted to slide along the axis relative to the sleeve and the spindle pulley, and the elongated spindle being adapted to rotate simultaneously with the sleeve and the spindle pulley. The drill press preferably includes a locking nut for connecting an upper end of the sleeve with the spindle pulley. The locking nut preferably has a central aperture aligned with the pulley central opening and the sleeve central opening, whereby the spindle extends through the locking nut central aperture. The drill press desirably includes a spacer disposed between an outer surface of the spindle and the locking nut central aperture for preventing the spindle from contacting the upper end of the sleeve during rotation of the sleeve and the spindle about the axis.
In one embodiment, the sleeve preferably has an upper end, a lower end, and the sleeve central opening between the upper and lower ends. The sleeve central opening desirably has a larger diameter section adjacent the sleeve upper end adapted for enabling the spindle to slide along the axis relative to the sleeve, and a smaller diameter section adjacent the sleeve lower end adapted to mesh with the spindle for transmitting rotation forces between the sleeve and the spindle while enabling the spindle to slide along the axis relative to the sleeve. The spindle preferably includes splines extending along a length of the spindle. The splines are preferably adapted to mesh with the smaller diameter section of the sleeve central opening for transmitting rotation forces from the sleeve to the spindle. The smaller diameter section of the sleeve preferably includes protuberances for transmitting rotational forces from the sleeve to the spindle. The splines are able to slide through the protuberances for enabling axial movement of the spindle relative to the sleeve.
These and other preferred embodiments of the present invention will be described in more detail below.
Referring to
The head stock 42 preferably includes a head stock pulley cover 62 that covers a drive system for supplying power to the spindle 48. In one embodiment, the drive system preferably includes a motor 64 that is coupled with the spindle 48 via one or more pulleys and drive belts, as will be described in more detail below. The head stock cover 62 is desirably moveable between the closed position shown in
Referring to
The drive system preferably includes a first drive belt 74 that extends about the motor pulley 66 and the center pulley 70. In one embodiment, the first drive belt 74 is preferably adapted to transmit power from the motor pulley 66 to the center pulley 70. In one embodiment, the first drive belt 74 is preferably a poly-v drive belt with v-shaped grooves formed on an inner face thereof, and the stepped pulleys have v-shaped grooves or projections adapted to mesh with the v-shaped grooves on the drive belts. In another embodiment, the drive belts may be conventional drive belts having a smooth inner face and the pulleys may have smooth stepped surfaces that mesh with the smooth inner faces of the drive belts. In other embodiments, any type of drive belt well-known to those skilled in the art may be used.
In one embodiment, the drive system preferably includes a stepped spindle pulley 76 that is coupled with the spindle 48 having an elongated shaft 78 and splines 80 extending along the axial length of the elongated shaft 78. The drive system preferably includes a second drive belt 82 that interconnects the rotatable center pulley 70 with the spindle pulley 76.
In one embodiment, the drive system preferably includes a spring-loaded drive belt tensioner 84 that is adapted to apply tension to an outer surface or face of one of the drive belts, such as disclosed in commonly assigned U.S. patent application Ser. No. 12/813,554, filed Jun. 11, 2010, the disclosure of which is hereby incorporated by reference herein. In one embodiment, the spring loaded tensioner 84 desirably applies tension to the outer face of the first drive belt 74. In one embodiment, the spring-loaded tensioner 84 uses spring force for automatically and continuously applying tension to the slack side and/or outer surface of the first drive belt 74 to maintain optimum tension on the first drive belt. As such, the motor associated with the motor pulley 66 may be rigidly mounted to the drill press, thereby eliminating several parts previously required in prior art systems for shifting the position of the motor for changing speeds, as well as the previously required extra machining on the head stock casting. Other benefits desirably include insuring that proper belt tension will always be maintained on the drive belts 74, 82, thereby eliminating user error when attempting to set the tension on the drive belts.
In one embodiment, the tensioner preferably applies tension to the slack side of the first drive belt 74. In one embodiment, the spring-loaded tensioner may be rotated in a counter-clockwise direction designated R1 for lessening the amount of tension applied by the tensioner 84 to the first drive belt 74 so that the position of at least one of the first and second drive belts 74, 82 may be changed for modifying the speed of the drill press. In one embodiment, zero tension is applied to the first drive belt 74 when the tensioner 84 is retracted. After the position of at least one of the first and second drive belts has been modified for changing the speed of the drive system, the spring-loaded tensioner may be rotated a clockwise direction designated R2 so that the belt tensioner 84 re-engages the first drive belt 74 for applying tension to the drive system. The tensioner preferably includes a spring that normally urges the tensioner 84 to rotate in the direction R2.
In one embodiment, the tension force applied by the spring-loaded tensioner 84 to the poly-V belt is according to the belt manufacturer's requirements. In one preferred embodiment, the spring-loaded tensioner 84 preferably engages the slack side of the first drive belt.
In one embodiment, the motor shaft 68 rotates the motor pulley 66 for driving the first drive belt 74. In turn, the first drive belt 74 rotates the center pulley 70 about the center pulley shaft 71. As the center pulley 70 rotates, the center pulley drives the second drive belt 82, which, in turn, rotates the spindle pulley 76. Rotation of the spindle pulley simultaneously rotates the spindle shaft 78, the chuck 50 and the drill bit 52 (
Referring to
Referring to
As noted herein, the elongated sleeve 98 is preferably affixed within the first central opening 96 of the stepped spindle pulley 76. As a result, when the stepped spindle pulley 76 is rotated by a drive belt 82 (
In one embodiment, the drive system preferably includes a spacer 110 having an axial opening 112 or central aperture. The spacer 110 is preferably adapted to slide over the outer surface of the spindle shaft 78 for assembling the spacer and a locking nut 120 together. The drive system preferably includes the locking nut 120 that is secured over the sleeve upper end 100. The locking nut 120 preferably couples the spindle pulley and the sleeve 98 together for simultaneous rotation. In one embodiment, the spacer 110 includes an outer surface having an annular groove 114 and the locking nut 120 includes an annular projection 124 that sits within the spacer annular groove 114. The spacer may be ring-shaped and may be made of non-metallic materials such as rubber, polymers and elastic materials. In one embodiment, the spacer may be a grommet.
In one embodiment, the central aperture of the spacer 110 defines a rounded, annular or ring-shaped inner surface. In one embodiment, the central aperture of the spacer 110 has a plurality of elongated grooves formed therein that are adapted to receive splines on an outer surface of the spindle. The elongated grooves formed within the central aperture of the spacer 110 preferably closely conform with and/or interface with the splines on the outer surface of the spindle as the spindle moves along a vertical axis relative to the spacer. In one embodiment, the spindle and the spacer are adapted to rotate simultaneously with one another about the vertical axis.
In one embodiment, the spacer 110 preferably includes an outer surface having an annular projection and the locking nut 120 has an inner surface including an annular groove that is adapted to receive the annular projection for coupling the spacer and the locking nut together. In one embodiment, the spacer 110 includes an outer surface having an annular groove with an O-ring disposed in the annular groove and the locking nut 120 has an inner surface including an annular groove that is adapted to receive the O-ring attached to the spacer for coupling the spacer and the locking nut together.
In one embodiment, the spacer 110 is positioned between the outer surface of the spindle and the locking nut for preventing the rotating spindle from rattling against the sleeve. In one embodiment, the spacer may be positioned between the upper end of the sleeve and the spindle for preventing the rotating spindle from rattling against the sleeve, such as by incorporating the spacer into the upper end of the sleeve.
Although the present invention is not limited by any particular theory of operation, it is believed that using a spacer that fits around a spindle shaft 78 for aligning it with the sleeve 98 prevents contact between the rotating spindle shaft 78 and the sleeve 98 for reducing noise found in prior art systems. In one embodiment, the spacer 110 is preferably made of a material that is soft enough to firmly hold onto the spindle shaft 78, while enabling the rotating spindle shaft 78 to freely move along the vertical axis A2. In one embodiment, using a spacer 110 between the locking nut 120 and the spindle shaft 78 preferably produces a drill press that is extremely quiet and that absorbs any manufacturing tolerances between the parts, particularly between the sleeve 98 and the spindle shaft 78. In one embodiment, the use of the spacer 110 and the locking nut 120 preferably reduces the noise level of an operating drill press to at least 2-5 decibels lower than may be obtained when using conventional drill presses, thereby providing a much quieter drill press.
Referring to
Referring to
In one embodiment, the outer portion of the locking nut 120 has wrench flats or other features which allow the locking nut to be properly assembled and/or torqued, with an inner diameter suitable for forming a mating fit with a grommet or other elastomeric material, and a height sufficient to accommodate the grommet and provide satisfactory clamping force on the pulley. Referring to
The headings used herein are for organizational purposes only and are not meant to limit the scope of the description or the claims. As used throughout this application, the word “may” is used in a permissive sense (i.e., meaning having the potential to), rather than the mandatory sense (i.e., meaning must). Similarly, the words “include”, “including”, and “includes” mean including but not limited to. To facilitate understanding, like reference numerals have been used, where possible, to designate like elements common to the figures.
While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, which is only limited by the scope of the claims that follow. For example, the present invention contemplates that any of the features shown in any of the embodiments described herein, or incorporated by reference herein, may be incorporated with any of the features shown in any of the other embodiments described herein, or incorporated by reference herein, and still fall within the scope of the present invention.
