GB2356168A

GB2356168A - A ratchet tool

Info

Publication number: GB2356168A
Application number: GB9926615A
Authority: GB
Inventors: Yu Tang Chen
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-11-11
Filing date: 1999-11-11
Publication date: 2001-05-16
Also published as: GB9926615D0

Abstract

A ratchet tool includes a pawl member 60 movably received in a recess 43 in an inside of the head of the tool, and a toothed wheel 50 received in the head. The pawl member 60 is engaged with the toothed wheel 50 and has a first side being a curved surface which has first teeth defined therein, an engaging portion 61 connected to a second side of the pawl member 60. A positioning device 44,45,46 is biasedly engage with the pawl member. A control member is movably engaged with the pawl member. The direction of rotation of the ratchet tool is determined by operating the control member. The positioning device preferably comprises a spring loaded, ball detent.

Description

2356168 RATCHET TOOL

FIELD OF THE INVENTION

The present invention re'lates to a ratchet, and more particularly, to an improved ratchet tool having a curved pawl member with more teeth engagable with the toothed surface of the toothed wheel in the head of the tool so as to provide a firm engagement when outputting a high torque.

BACKGROUND OF THE INVENTION

A conventional wrench as shown in Fig. I generally includes two ends I I connected between a handle 10 and one of the ends I I as shown is a boxend having a polygonal central hole 2 for engaging a nut. The two ends I I are located on the same plane as tile handle 10 is located so that when using the wrench the handle I I could be impeded by other parts around the nut to be tightened or1oosened. Figure 2 shows another wrench wherein the two ends are located on different planes with respect to the plane that the handle 10 is located so that when the wrench is engaged with the bolts 12, the handle 10 is located above the surface on which the bolts 12 are located. Nevertheless, the wrench has to be disengaged from the bolt 12 when rotatin g the bolt 12 to an angle, and then to engage with the bolt 12 again at the original position so as to rotate another arc length. A ratchet tool as shown in Figs. 3 and 4 is developed and includes a handle 20 with a head. A pawl member 22 is biased by a spring 23 and both are received in a recess 202 defined in an inside of the central bole 201 of the head and the pawl member 22 is engaged with the toothed wheel 21. The ratchet tool is allowed to be rotated reciprocatingly without disengaging the tool fom the object engaged with the tool. Such a wrench is disclosed in U.S. Patent No. 5,636,557. However, the wrench cannot overcome the disadvantage as illustrated and described with respect to the wrench shown in Fig. 1, and the wrench can only output torque in one direction. To improve the shortcoming, a ratchet tool as shown in Fig. 5 is developed and also discloed in U.S. Patent No.

5,884,538, U.S. Patent No. 5,626,062,, and U.S. Patent No. 5,782,147. The ratchet too] has a pawl member 32 which has two toothed ends and is pivoted about a pin in the center of the pawl member 32 by shifting a control bar on an outside of the bead 30 of the tool. Either one of the toothed ends is controlled to be engaged with the toothed wheel 3 1. Accordingly, the ratchet tool can be effectively rotated in two different directions and each of which can output a torque. An inherent shortcoming of the ratchet tool shown in Fig. 5 is that the numbers of the teeth on each of the two toothed ends are few so that when an high torque is required, the less number of teeth engagement cannot afford to generate such a high torque.

The present invention intends. to provide a ratchet tool having a curved pawl member which has teeth defined in the curved surface so as to engage with the toothed wheel so that a high torque can be reached. The ratchet tool has a compact head portion and simple structure. I SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention, there is provided a ratchet tool comprising a head having a central hole and a recess define in an inside defining the central hole. A pawl member has a first side being a curved surface having first teeth defined in the curved surface, and an engaging portion connected to a second side of the pawl member. The pawl member is movably received in the recess and a positioning means is biasedly engage Yrith the engaging portion. A toothed wheel is received in the central hole of the head and the pawl member is engaged with the toothed wheel. A control member is movably engaged with the pawl member.

The object- of the present invention is to provide ratchet tool having a 25 curved VdWI member having teeth on the curved surface and the teeth are engaged with the.toothed wheel in the head of the ratchet tool so as to bear a large torque wben applied.

2 These and further ob. ects, features and advantages of 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, several embodiments in accordance with the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. I is a plan view to show a conventional wrench; Fig. 2 shows another conventional wrench engaged with a bolt on a surface; Fig. 3 shows a conventional one-directional ratchet wrench; Fig. 4 is an exploded view to show the conventional one-directional ratchet wrench as shown in Fig. 3; Fig. 5 is an illustrative view to show yet another conventional ratchet tool; Fig 6 is an exploded view to show the ratchet tool in accordance with the present invention; Fig 7 is a side elevational view, partly in section, of the ratchet tool of the present invention; Fig. 8 is a side elevational. view, partly in section, of the ratchet tool wherein the ball of the positioning means is located at one side of the protrusion of the pawl member of the present invention; Fig. 9 Is a side elevational view, partly in section, of the ratchet tool wherein the tip of the protrusion of the pawl member is to be moved to roll over the ball of the positioning means; Fig. 10 is a side' elevational view, partly in section, of the ratchet tool wherein the ball of the positioning means is located at the other side of the protrusion of the pawl member of the present invention; Fig. I I is an exploded view to show another embodiment of the pawl member and the control member of the ratchet tool of the present invention; 3:

Fig. 12 is a side elevational view, partly in spction, of the ratchet tool wherein the pawl member and the control member are illustrated in Fig. 11; Fig. 13 is an exploded view to show yet another embodiment of the pawl member and the control member of the ratchet tool of the present invention; Fig. 14 is a side elevational view, partly in section, of the ratchet tool wherein the pawl member and the control member are illustrated in Fig. 13; Fig. 15 shows another embodiment of the connection of the control member and the pawl member; Fig. 16 shows another embodiment of the connection of the control member and the pawl member; Fig. 17 is an exploded view to show another embodiment of the connection of the control member and the pawl member, wherein the toothed wheel has an engaging rod extending therefrom; - Fig. 18 is a cross-sectional view to show the ratchet tool as shown in Fig.

17; Fig. 19 is a perspective view to show another embodiment of the ball of the positioning means; Fig. 20 is a plan view to show the ball as shown in Fig. 19 engaged with the engaging portion of the pawl member; Fig. 21 is an exploded view to show that the ratchet tool of the present invention.is used as a one-directional ratchet tool; Fig. 22 is a perspective view to show the head of the ratchet tool as shown in Fig. 21; Fig. 23 is an illustrative view to show the engagement of the positioning means and the pawl member of the ratchet tool as shown in Fig. 21; Fig. 25 isan illustrative view to show another embodiment. of the engaging portion of the pawl member, and 4 Fig. 26 is an illustrative view to show yet another embodiment of the engaging portion of the pawl member.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to Figs. 6 to 10, the ratchet too] in accordance with the present invention comprises a head 41 with a shank or handle 47 extending from the head 4 1.

The head 41 has a central hole 42 defined therethrougb and a recess 43 is defined in an inside defining the central hole 42. A chamber 44 is defined in a bottom defining the recess 43 so that a positioning means including a ball 46 and a spring 45 are respectively received in the chamber 44. A toothed wheel 50 is received in the central hole 42 of the head 41 and has teeth 51 defined in the outside of the toothed wheel 50. A flange 52 extends from one of two ends of the toothed wheel 50 and has a groove 53 defined therein so as to receive a ring 80 therein. The ring- shaped toothed wheel 50 has a polygonal inside so as to engage an object such as a nut or a bolt head.

A pawl member 60 is received in the recess 43 and has a first side being a curved surface having first teeth 63 defined in the curved surface, and an engaging portion 61 is connected to a second side of the pawl member 60' The second side located on an opposite side of the curved surface of the pawl member 60 and the engaging portion 61 is a triangle protrusion with two inclined sides in this embodiment. The ball 46 is biased and located one either one of the two inclined sides of the triangle protrusion. The first teeth 63 of the pawl member 60 are engaged with the teeth 51 of the toothed wheel 50. The pawl member 60 has a stepped surface 6.,.: defined in the curved surface and the stepped surface 62 has second teeth defined therein.

A control member 70 being a ring member is movably engaged with the head 41 and has an annular groove 74 so as to receive the ring 80. A serrated surface 72 is defined in an upper surface of the control member 70 so Ahat a user can easily rotate the control member 70. The control member 70 further has third teeth 73 defined in an outer surface thereof so as to engage the second teeth in the stepped surface 62 of the pawl member 60. Therefore, when rotating the control member 70, the pawl member 60 is shifted. When one end of the pawl member 60 contacts the inside of the recess 43, as shown in Fig. 8 or 10, when the toothed wheel 50 is rotated to make the pawl member 60 move toward the inside of the recess, a torque can be output. Therefore, the pawl member 60 can be shifted and the engaging portion 61 retains the ball 46 at the desired position. In other words, the tip of the triangle engaging portion 61 can move over the ball 46 as shown in Fig. 9. It is to be notedihat the numbers of the first teeth 63 and teeth 51 of the toothed wheel 50 are enough to bear a large torque.

Figures I I and 12 show that the engaging portion 61 extends from an upper end of the pawl member 60 and has a notch 64 defined therein, and the control member 70 has a boss 75 extending radially outward from the control member 70 so that the boss 75 is engaged with The notch 64 and when the control member 70 is rotated,- the pawl member 60 is moved.

Figures 13 and 14 show that the head 41 has an aperture 48 defined tberethrough and communicating with the recess 43. A switch member 90 is movably connected to the head 41 and has a pin 91 extending through the aperture 48. The pawl member 60 has a hole 65 defined in the upper end thereof so that the pin 91 is engaged with the hole 65 so as to achieve the same movement feature by shifting the switch member 90.

Figure 15 shows that the control member 70 has a positioning pin 76 extending toward the pawl membq 60 having the hole 65 so that the positioning pin 76 is engaged with the hole 65. Figure 16 shows that the control member 70 has a cut-away or groove 77 defined in a bottom thereof and the pawl member 60 is 6 partially engaged with the groove 77 so that when the Control member 70 is rotated, the pawl member 60 is shifted.

Figures 17 and 18 show that the pawl member 60 has a rod 68 extending radially outward therefrom and the rod 68 is retained in the groove 17. It is to be noted that a rectangular engaging rod 500 extends from the toothed wheel 50 so as to engage with objects. Figures 19 and 20 show that the shape of the ball 46 can be a semi-spbere.

Figures 21 to 23 show that the ratchet tool can also be manufactured as-. a one-directional ratchet tool. The pawl member 60 is retained in the recess 43 in the head 41 and one of two ends of the pawl member 60 contacts the inside of the recess 43. The pawl member 60 is positioned by the ball 46. Figure 24 shows that the engaging portion of the pawl member 60 is a semi-circular recess 66 and the ball 46 is retained in the semi-circular recess 66. Figure 25 shows that the second side of the pawl member 60 is a convex surface and the engaging portion 67 is a plan s drface defined in the convex surface of the pawl member 60 so that the ball 46 contacts the plan surface.

While we have shown and described various embodiments in accordance with the present invention, it should be clear to those skilled in the art that ftirther embodiments may be made without departing from the scope and spirit of the present invention.

i I 7

Claims

1. A ratchet tool comprising:

a head havino a central We defined thrOLI(Ill said head and a recess defined C) r> in-an inside defining, said central hole, a pawl member having a first side being a J- cbrved surface having first teeth defined in said curved surface, an engaging portion connected to a second side of said pawl member, said second side located on an opposite side of said Curved surface of said pawl member, said pawl member movably received in said recess and a positioning means biasedly engage with said engaging portion of said pawl member; a toothed wheel received in said central hole of said head and said pawl member engaged with said toothed wheel, and L" control member movably engagedwith said pawl member.

0

2. The ratchet tool as claimed in claim 1, wherein said pawl member has a step ped surface defined in said curved surface and said stepped surface has second 1.5 tee th defined therein, said control member having third teeth defined in an outer stifface thereof, said second teeth of said pawl member engaged with said third teeth.

3. The ratchet tool as claimed in claim 1, wherein said positioning means I includes a ball and a spring which urges said.ball onto said engaging portion.

4. The ratchet tool as claimed in claim 3, wherein said engaging portion of 20..said pawl member is a trian ale protrusion Aitb two inclined sides, said ball is located bne either one of said hvo inclined sides of said triangle protrusion.

5. The ratchet tool as claimed in claim 3, wberein said engaging portion of said pawl member is a semi-circular recess and said ball is retained in said semi-circular recess.

6. The ratchet tool as claimed in claim 3, wherein said second side of said pawl member is a convex surface and said engaging portion is a plan surface defined in said convex surface of said pawl member, said ball contacting. said plan stLrface.

8

7. The ratchet too] as claimed in claim 1, whereip said pawl member has a notch and said control member has a boss extending radially outward from said control member, said boss engged with said notch.

8. The ratchet tool as claimed in claim L wherein said control member has a groove defined in a bottom thereof and said pawl member is partially engaged with said groove.

9. 'Me ratchet tool as claffned in claim 1, wherein said control member has a groove defined in a bottom thereof and said pawl member has a rod extending radially outward therefrom, said rod being retained in said groove.

9