MXPA06008085A - Rotating shaft locking mechanism - Google Patents

Abstract

A locking mechanism (10) for a rotary power tool that includes an elongated locking member (32) that is retained by, and is at opposite first and second end portions within, at least one of a motor housing (12) and a gearbox end casting (14) and being slideable between unlocked and locked positions, the locking member (32) first end portion (34) being accessible by a user to move the locking member to the locked position. The locking member (32) also includes a locking portion (44) intermediate the first and second end portions (36) that is configured to engage the non-circular configured portion (48) of a rotatable armature shaft (50) and prevent rotation thereof when the locking member is in its locked position. A biasing element (58) is also included and configured to bias the locking member toward said unlocked position.

Description

Published: For two-letter codes and other abbreviations, refer to the "Guid- - with intemational search report" Notes on Codes and Abbreviations "appearing at the begin- - before the expiration of the time limit for amending the ning ofeach regular issue ofthe PCT Gazette. claims and to be republished in the event of receipt of amendments ROTATING AXIS LOCKING MECHANISM FIELD OF THE INVENTION The present invention generally relates to motorized hand tools and very particularly to a shaft locking mechanism for those tools.

BACKGROUND OF THE INVENTION Many motorized hand tools have rotary cutting blades, grinding blades and other rotary tool attachments that can be mounted on a frame shaft of an electric motor that drives the rotating blade or the like. To change blades or other tools that are mounted in this manner, prior art systems have been designed and developed that allow the user to keep the blade stationary while removing a mounting nut or bolt. One way in which this has been done in the past is to make the base frame shaft produce a pair of opposing flat surfaces that can be attached by means of a wrench or the like to hold the shaft while loosening or removing the nut . However, a problem with the flat surfaces of rectification in the shaft is that the flat surfaces necessarily weaken the shaft, which may require the use of a reserve metal shaft of larger diameter to compensate for the loss of resistance resulting from the rectification of flat surfaces.

SUMMARY OF THE INVENTION Other systems use one or two holes in a gear or gear hub that is fixed to the output shaft where a leg or other protrusion is inserted to hold the shaft while removing the mounting nut. Another problem with these two configurations of the prior art is that there are only one or two couplings per revolution of the blade, which causes some inconvenience in the rapid locking of the shaft. Even other systems of the prior art have used a blocking element which is a complementary gear that engages a tool output gear, which can create unnecessary wear of the gear and reduce its useful life, particularly if the user places the portion of braking gears in contact with the output gear while the shaft is still rotating. One goal of the designers is to develop a spindle lock mechanism that is economical, effective and convenient for coupling, and that does not damage output gears or the like during operation. A preferred embodiment of the spindle lock mechanism of the present invention comprises a preferably stamped, elongated steel locking element that is configured to fit within the slotted openings in at least one of the end molding of the motor housing and the main housing, which comprises the blocking element having a spindle lock configuration which can be moved in engagement with a hexagonal bearing which is preferably press fit onto the output shaft of the motor frame, and the which, normally, is deviated from the axis of the frame.

BRIEF DESCRIPTION OF THE FIGURES Figure 1 is a front perspective view of a circular saw having a portion of the locking mechanism embodying the present invention illustrated therein; Figure 2 is a diagrammatic plan view of the shaft locking mechanism assembled in a motor; Figure 3 is a perspective side view of the portions of a motor that are used in the circular saw shown in Figure 1, and which is illustrated together with the end molding of the gearbox and a large portion of the shaft locking mechanism embodying the present invention; Figure 4 is a view of the interior of the end molding of the gearbox where substantially the axle locking mechanism resides; Fig. 5 is a perspective view of the end molding with the motor blocking element shown with the major portions of the motor; Figure 6 is a perspective view of the blocking element; Figure 7 is a side view of the blocking element shown in Figure 6; Figure 8 is a top view of the blocking element shown in Figure 6; Fig. 9 is a top view of a hexagonal shaped bearing that is pressurized on the axle of the frame; and Figure 10 is a side view of the hexagonal bearing shown in Figure 9.

DETAILED DESCRIPTION OF THE INVENTION Although the preferred embodiment of the shaft locking mechanism of the present invention is shown with a circular saw, it should be understood that the mechanism can be adapted for use with other types of tools, wherein a blade or shaft Rotary outlet needs to be held in place while loosening a blade bolt or blade nut so that a blade or other tool can be removed or installed. Turning now to the figures, and particularly FIGS. 1 and 2, there is shown a circular saw with a portion of the preferred shaft locking mechanism, indicated generally by the numeral 10, which is shown at an interface between a main motor housing 12. and an end molding of the gearbox 14 which appears to have a number of blinds 16 through which air comes out during the operation of the motor, which has an associated fan blade 18 (FIG. 3). The circular saw has a saw blade housing 20 surrounding a saw blade (not shown) and an auxiliary handle 22 as well as a base 24 having a bevelled dial structure 26 and a locking mechanism 28. Saw blade, in turn, is coupled to a spindle or frame shaft 30 of an electric motor (not shown) which drives the saw blade or the like. Turning now to FIG. 6, the preferred shaft locking mechanism 10 includes an elongated locking element 32 having front and rear end portions 34, 36 with a spindle lock portion, generally designated with the number 38, positioned by the regular in the middle of the front and rear end portions. The front end portion 34 includes a front longitudinal portion 40 extending through a slot 42 or other opening which is preferably located at the end molding interface of the gear case 14 and the motor housing 12. At an outer end of the front longitudinal portion 40 is a transverse end 44, which can be pushed by the operator inward to engage the spindle and lock it against rotation so that the saw blade can be removed. More specifically, going back to Figure 2, it can be selectively avoided that the frame shaft 30 rotates by lockingly engaging the spindle lock portion 38 of the elongate locking element 32 to the frame axis. Therefore, the spindle lock portion 38 can oscillate between a locked position and an unlocked position. For this purpose, the elongated locking element 32 is spring-biased outward in an unlocked position so that the spindle locking portion 38 of the locking element does not engage the shaft of the frame 30 unless the operator selectively Apply enough force to move it inward toward the axis of the frame, which is the locked position. As illustrated in Figure 4, in order to retain the blocking element 32, the end molding of the gearbox 14 preferably includes front and rear cavities 46, 48 which generally oppose each other diametrically. The front end portion 34 of the blocking element 32 engages the front cavity 46, which is preferably placed in one of the blinds 16, while a distal end of the rear end portion 36 is preferably retained within the rear cavity 48, which is located in the opposite rear wall of the end molding 14. The blinds 16 extend from a side wall 49 so that the distal surfaces thereof extend a predetermined distance from the side wall. Although the distal surfaces of some of the blinds 16 are flat, the front cavity 46 is preferably formed by two blinds that each include at least two surfaces that are displaced, in elevation, from each other. More specifically, as illustrated in Figure 4, the two blinds 16 that are in the middle of the upper and lower blinds each include two surfaces displaced in elevation. A first blind 16 includes a first surface 16a and a second surface 16b, wherein the first surface extends a greater distance from the side wall 49 than the second surface. In the other blind 16 the third and fourth surfaces 16c, 16d are provided, wherein the third surface 16c extends a greater distance from the side wall 49 than the fourth surface 16d. However, the second surface 16b and the third surface 16c are generally coplanar. Therefore, the distal surfaces of the two blinds 16 which are in the middle of the upper and lower blinds provide a reduced profile, creating the front cavity 46. Accordingly, the cavities and the motor housing 12 provide support for the blocking element. 32, where the element can slide in and out, that is, to the right and to the left, respectively, as shown in figure 2. To provide greater support, as shown in figures 2, 6 and 8, the longitudinal portion 40 extending outside the housing, preferably includes an elongated width at the location 50 defining bras 52 which engage the inner wall of the motor housing 12 and prevent it from moving to the left, as shown in FIG. shown in Figure 2. The spindle lock portion 38 is configured to lockly engage a bearing 54 which is press fit into the axis of the frame 30.

Although the spindle lock portion 38 and the bearing 54 can assume any of a plurality of corresponding configurations, the preferred embodiment includes a hexagonal bearing. Accordingly, the spindle lock portion 38 of the preferred embodiment is configured to be generally one half of a hexagonal head configuration 56 for coupling the hexagonal bearing 54. An extension 58 of the spindle lock portion 38 surrounds partially the hexagonal bearing 54 and then generally extends radially towards the rear cavity 48 of the end molding of the gearbox 14. The rear end portion 36 extends from the extension 58 to preferably engage and be retained Within, the rear cavity 48. Therefore, the blocking element 32 extends from an external position to the motor housing 12 and the end molding of the gearbox 14, through the front cavity 46, through of an internal diameter of the end molding of the gearbox 14, with the rear end portion 38 preferably engaging the rear cavity 48. As shown in FIG. can be better appreciated in Figures 2 and 3, a biasing element, preferably a compression spring 60, is provided to bias the locking element 32 in the unlocked position. More specifically, the locking element 32 preferably includes a narrow elongate protrusion 62 positioned within a portion of the front end portion 34 (Figure 6), wherein, preferably, the protrusion is placed over the compression spring 60. The protrusion 62 preferably includes a first base diameter and a second shaft diameter, wherein the base diameter is at least slightly larger than the shaft diameter. As best illustrated in Figures 2 and 4, one end of the compression spring 60 is wound more tightly around the base diameter, and abuts a surface in the base diameter of the protrusion 62, while an opposite end of the compression spring 62 engages a housing receptacle 64. Therefore, the spring 60 biases the blocking element 32 to the left, as shown in Figure 2 so that the spindle lock portion 38 does not engage the bearing in hexagonal form 54. However, when the operator exerts sufficient force on the transverse end 44 of the front end portion 34, the spring 60 is compressed to allow the displacement of the blocking element 32, specifically the spindle lock portion 38. , to couple the bearing 54 and prevent rotation of the shaft of the frame 30. At the moment of releasing the transverse end 44, the spring 60 will cease to exert compression to bypass the element or locking 32 back to the left, as illustrated in Figure 2. Although it is contemplated that the bearing 54 can be configured in one of a plurality of ways, the hexagonal head bearing is particularly convenient as it does not require cutting some of the axle of the frame 30 and is economical and effective, requiring only the press fit of the bearing with the axle of the frame. The use of a hexagonal head configuration for the spindle lock portion 38 and for the bearing 54 is preferred, although other configurations such as a square, octagon, grooves or notches could be used. An additional advantage of the hexagonal head is that there is a coupling with the bearing 54 every 60 ° of rotation of the saw blade. Although various embodiments of the present invention have been shown and described, those skilled in the art will appreciate that other modifications, substitutions and alternatives can be made. These modifications, substitutions and alternatives can be made without departing from the spirit and scope of the invention, which should be determined from the appended claims. Several characteristics of the invention are mentioned in the following claims.

Claims (18)

NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following is claimed as a priority: CLAIMS

1. - A locking mechanism (10) for a rotating motorized tool of the type having a main motor housing having a rotating frame shaft with a non-circular shaped portion, a gear case end molding fixed to the motor housing, said locking mechanism comprises: an elongate locking element (32) which is retained by, and is in the first and second opposite end portions (34, 36) within at least one of the motor housing (12) and the end molding of the gear case (14) and which can be slid between the locked and unlocked positions, the user can have access to the first end portion of the locking element to move said locking element to said locked position. said locking element has a locking portion (38) in the middle of said first and second end portions which is configured to engage the non-circular shaped portion (54) of the armature shaft. rotating and preventing the rotation thereof when said locking element is in its locked position; and a deflecting element (60) configured to deflect said locking element toward said unlocked position.

2. The mechanism according to claim 1, characterized in that the non-circular configuration portion comprises a bearing fixed to the rotating frame shaft.

3. The mechanism according to claim 2, characterized in that said bearing is configured to have a hexagonal shape.

4. The mechanism according to claim 2, characterized in that said locking portion is configured to correspond at least partially blocked with said bearing.

5. The mechanism according to claim 4, characterized in that said blocking portion is configured approximately one half of a hexagon.

6. The mechanism according to claim 1, characterized in that the first end portion of said elongated locking element is configured to extend outwardly, through an interface between the main motor housing and the end molding. of the gearbox.

7. The mechanism according to claim 1, characterized in that said second end portion of said elongated locking element is configured to engage a rear wall of the end molding.

8. The mechanism according to claim 1, characterized in that said first end portion comprises an annular support configured to couple a front wall of the end molding.

9. The mechanism according to claim 6, further comprising a transverse end of said blocking element.

10. The mechanism according to claim 1, characterized in that the end molding of the gearbox includes a first and second cavities that are generally diametrically opposed to each other, and said first end portion is retained within the first cavity and said second end portion is retained within said second cavity.

11. A locking mechanism (10) for a rotating motorized tool of the type having a main motor housing comprising a rotating frame shaft with a non-circular shaped portion, an end molding of the gear box (14) fixed to the motor housing, said locking mechanism comprises: locking means (38) for lockingly coupling the non-circular shaped portion of the rotating frame shaft and preventing rotation thereof; reciprocation means (40) for reciprocating the locking means between a locked position and an unlocked position; retaining means (46, 48) for retaining said reciprocation means within the end molding of the gearbox and the motor housing; and diverting means (60) for biasing the locking means in the unlocked position.

12. The locking mechanism according to claim 11, characterized in that said reciprocating means comprise an elongate element having a first end portion and a second end portion that are retained within diametrically opposed portions of the end molding. the gear box.

13. The locking mechanism according to claim 12, characterized in that said locking means comprise a blocking portion in the middle of said first end portion and said second end portion that is configured to lockly engage the configured portion. not circulate

14. - The locking mechanism according to claim 13, characterized in that said locking means comprise a hexagonal head configuration in half.

15. The locking mechanism according to claim 12, characterized in that said first end portion extends out of the end molding of the gearbox and the motor housing.

16. The locking mechanism according to claim 15, further comprising a contact portion positioned at an outer end of the first end portion to be contacted by an operator and to be pushed into a locked position.

17. The locking mechanism according to claim 12, characterized in that said retaining means comprise a first cavity and a second cavity placed in the end molding of the gearbox which, in general, are diametrically opposed to each other. , said first cavity is configured to retain said first end portion and said second cavity is configured to retain said second end portion.

18. The locking mechanism according to claim 11, characterized in that said deflection means comprise a compression spring that is configured to deflect said locking means to the unlocked position.