FIELD OF THE INVENTION
The present invention relates to a multiple gearing switch device that employs a switch assembly and an idle gear set to operate a planetary gear speed reduction device so as to obtain multiple output speeds in desired directions.
BACKGROUND OF THE INVENTION
Conventional electric tools, especially those including spinning device, generally employ a speed reduction device to provide multiple gearing feature and have different output torques. The speed reduction device includes a planetary gear system including a sun gear, a plurality of planet gears, inner gears and a disk. These gears and disk are arranged to play different roles, such as input or output members, so as to have different output speeds. Nevertheless, complicated assembling and/or manufacturing difficulties are involved in the existing electric tools with multiple gearing switch device such that high price and risk of maintenance are commonly seen, which does not satisfy the users. Besides, only two or three speeds can be chosen because of limitations of the conventional gearing switch device.
Therefore, it is desired to have a gearing switch device that is able to improve one or more problems existing in the conventional gearing switch device.
SUMMARY OF THE INVENTION
In accordance with an aspect of the present invention, there is provided a gearing switch device that comprises a casing in which a speed reduction device is received and includes a disk which has a plurality of planet gears on a first side of the disk and an input gear is located between and engaging the planet gears. An output gear is connected to the other side of the disk. A ring gear has inner teeth engaging the planet gears, and outer teeth engaging two transferring gears connected to the casing. A switch assembly has a switch member with a plurality of recesses defined in an outer periphery thereof and the transferring gears are located in the recesses. Each recess has engaging teeth defined in a side thereof. A protrusion extends radially outward from the switch member and through a slot defined through a wall of the casing. A plurality of idle gear sets is connected to a side of the switch member and each has a first idle gear and a second idle gear. Teeth of each of the first idle gear and the second idle gear are located in alignment with the engaging teeth of the recesses. The first idle gear and the second idle gear are located at different radial positions such that only one of the first idle gear and the second idle gear is engaged with the input gear in the same time. One of the first and second idle gears or the engaging teeth selectively engage the transferring gears.
The present invention will become more obvious from the following description when taken in connection with the accompanying drawings, which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded view of a gearing switch device in accordance with the present invention;
FIG. 2 shows an input gear engaging planet gears which engage a ring gear and two transferring gears engage the ring gear,
FIG. 3 shows the flexible boss on the casing is engaged with one of the notches of the switching knob
FIG. 4 shows that the teeth of the insides are engaged with the transferring gears and the first idle gears are engaged with the input gear,
FIG. 5 shows that the first idle gears are engaged with the transferring gears and the input gear;
FIG. 6 shows that the second idle gears are engaged with the transferring gears and the first idle gears are engaged with the input gear;
FIG. 7 shows that the first idle gears are composed of an upper gear and a lower gear;
FIG. 8 shows that the second idle gears are composed of an upper gear and a lower gear;
FIG. 9 shows that the input gear is composed of an upper portion and a lower portion, and
FIG. 10 shows that the transferring gear is composed of an upper transferring gear and a lower transferring gear.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings and in particular to FIGS. 1 and 2, a gearing switching device of the present invention is received in a receiving space 21 defined in a casing 2 of a tool that is not shown. The gearing switching device comprises an input gear 1 and a speed reduction device 3 is received in the casing 2 and has a disk 31 that has four planet gears 32 on a first side of the disk 31 and the input gear 1 is located between and engaged with the planet gears 32. An output gear 31a is connected to the other side of the disk 31 and drives an output shaft that is not shown. A ring gear 33 has inner teeth 33a in an inner periphery and outer teeth 33b in an outer periphery of the ring gear 33. The planet gears 32 are engaged with the inner teeth 33a, and two transferring gears 34 are connected to the casing 2 and engaged with the outer teeth 33b.
A switch assembly 4 has a switch member 41 with a central hole 41a for the input gear 1 to extend therethrough and two recesses 41b are defined in an outer periphery of the switch member 41 such that the transferring gears 34 are located in the two recesses 41b. Each recess 41b has engaging teeth 41c defined in a side thereof. A protrusion 41d extends radially outward from the switch member 41 and through a slot 22 defined through a wall of the casing 2. Further referring to FIG. 3, a switching knob 42 is connected to the protrusion 41d and has a plurality of notches 42a. A flexible boss 23 extends from an outer periphery of the casing 2 and located beside the slot 22. The flexible boss 23 is engaged with one of the notches 42 when the switching knob 42 is shifted by the user.
Two idle gear sets 5 are connected to a side of the switch member 41 and each idle gear set 5 has a first idle gear 51 and a second idle gear 52. Teeth of each of the first idle gear 51 and the second idle gear 52 are located in alignment with the engaging teeth 41c of the recesses 41. The first idle gear 51, the second idle gear 52 and the engaging teeth 41c are located at different radial positions such that only one of the first idle gear 51, the second idle gear 52 and the engaging teeth 41c can be engaged with the input gear 1 in the same time.
Referring to FIG. 4, when shifting the switching member 41 by shifting the switching knob 42 to a position as shown, only the engaging teeth 41c are engaged with the transferring gears 34, so that transferring gears 34 are stationary. Because the transferring gears 34 are engaged with the ring gear 33 so that the ring gears 33 is stationary. Therefore, the power brought by the input gear 1 drives the planet gears 32, the first idle gears 51 and the second idle gears 52. The first idle gears 51 and the second idle gears 52 do not drive any part and the planet gears 32 are rotated in the ring gear 33 so that the speed of the disk 31 together with the output gear 31a is reduced. The output torque is increased.
Referring to FIG. 5, when shifting the switching member 41 to another position as shown, the first idle gears 51 are engaged with the transferring gears 34 and driven by the input gear 1. The transferring gears 34 rotate in the same direction as the input gear 1. The transferring gears 34 drives the ring gear 33 so that the power brought by the input gear 1 drives the planet gears 32, the first idle gears 51 and the second idle gears 52 which do not drive any part. The planet gears 32 are rotated relative to the ring gear 33 so that the speed of the disk 31 together with the output gear 31a is reduced. The output torque is increased.
Referring to FIG. 6, when the switching member 41 is shifted to yet another position as shown, only the second idle gears 52 are engaged with the transferring gears 34 and the second idle gears 52 are driven by the first idle gears 51 which is driven by the input gear 1. The transferring gears 34 rotate in the opposite direction of the input gear 1. The transferring gears 34 drives the ring gear 33 so that the power brought by the input gear 1 drives the planet gears 32, the first idle gears 51 and the second idle gears 52. The planet gears 32 are rotated relative to the ring gear 33 so that the speed of the disk 31 together with the output gear 31a is reduced. The output torque is increased.
It is noted that the power from the input gear 1 is transferred to the speed reduction device 3 via the idle gear set 5 and the transferring gears are driven by the idle gear set 5 to drive the ring gear 33 at different speed and directions so as to obtain different speed and directions for the disk 31 and the output gear 31a. Therefore, different types of arrangement of the idle gear set 5, the transferring gears 34 and the input gear 1 may obtain multiple gearing functions, and are described hereinafter.
Referring to FIG. 7, the first idle gear 51 that is engaged with the input gear 1 of each of the idle gear sets 5 includes an upper gear 51a and a lower gear 51b that is co-axially connected to the upper gear 51a. The upper gear 51a and the lower gear 51b have different number of teeth. The upper gear 51a is engaged with the second idle gear 52 and the lower gear 51b is engaged with the transferring gear 34.
Referring to FIG. 8, the second idle gear 52 that is not engaged with the input gear 1 of each of the idle gear sets 5 includes an upper gear 52a and a lower gear 52b which is co-axially connected to the upper gear 52a. The upper gear 52a and the lower gear 52b have different number of teeth. The upper gear 52a is engaged with the first idle gear 51 and the lower gear 51b is engaged with the transferring gear 34.
Referring to FIG. 9, the input gear 1 includes an upper portion 11 and a lower portion 12 that is co-axially connected to the upper portion 11. The upper portion 11 and the lower portion 12 have different number of teeth. The upper portion 11 is engaged with the first idle gear 51, and the lower portion 12 is engaged with planet gears 32.
Referring to FIG. 10, the transferring gear 34 includes an upper transferring gear 34a and a lower transferring gear 34b that is co-axially connected to the upper transferring gear 34a. The upper transferring gear 34a and the lower transferring gear 34b have different number of teeth. The upper transferring gear 34a is engaged with one of the first idle gear 51 or the second idle gear 52 in the same idle gear set 5 and the lower transferring gear 34b is engaged with the gear ring 33.
It is also noted that a number of the gears in each of the idle gear set 5 can be increased, or adding some gears that can change speed in the idle gear set 5 so as to obtain more options of the gearing features.
While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.
Patent Application
20050192149
