Strap tightener

Details Strap tightener Strap tightener

2001-04-18

2002-10-01

Matecki, Kathy (Department: 3654)

Implements or apparatus for applying pushing or pulling force

Portable implements or apparatus for tensioning flexible...

Including rotatably driven drum for engaging either material...

C024S0680CD

Reexamination Certificate

active

06457701

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a tightener, and more particularly to a strap tightener that has less wear between the pivot pin and the lever and the wing plates when releasing the strap.
2. Description of Related Art
With reference to
FIGS. 5 and 6
, a conventional strap tightener in accordance with the prior art comprises a base plate (
50
), a U-shaped seat (
60
), a lever (
70
) and a ratchet device. The U-shaped seat (
60
) is mounted on the base plate (
50
). The lever (
70
) is pivotally mounted on the seat (
60
) by a pivot pin (
80
). The ratchet device is mounted between the lever (
70
) and the seat (
60
).
The base plate (
50
) has a distal edge and a proximal edge parallel to each other. The distal edge of the base plate (
50
) is bent to form a hook (
500
). A slot (
52
) with two ends is defined in the base plate (
50
) near and parallel to the proximal edge through which a strap (
100
) can pass. A pair of ears (
51
) extends perpendicular from the base plate (
50
) in a direction opposite to the hook (
500
) near the distal edge of the base plate (
50
). The ends of the slot (
52
) correspond to the respective ears (
51
). Each of the ears (
51
) has a through hole (
511
) defined to align with the through hole (
511
) in the other ear (
51
). A bore (
53
) is defined in the base plate (
50
) between the pair of ears (
51
) and the slot (
52
).
The seat (
60
) includes two wing plates (
600
) parallel to each other. The wing plates (
600
) are oriented perpendicular to the proximal and distal edges of the base plate (
50
), have first ends near the distal edge of the base plate (
50
) and second ends near the proximal edge of the base plate (
50
). The wing plates (
600
) are connected by a bridge (
601
) to form a U-shape. A retaining plate (
602
) extends upward from one side of the bridge (
601
) near the pair of ears (
51
), and a hole (
604
) is defined in the retaining plate (
602
). A through hole (
61
) is defined in the first end of each wing plate (
600
) to correspond to the through holes (
511
) in the ears (
51
). A through hole (
603
) is defined in the bridge (
601
) and corresponds to the bore (
53
) in the base plate (
50
). After the through holes (
61
) in the wing plates (
600
) align with the through holes (
511
) in the ears (
51
), a bolt (not numbered) extends through the bore (
53
) in the base plate (
50
) and the through hole (
603
) in the bridge (
601
). A pivot hole (
62
) is defined in the second end of each of the wing plates (
600
), and a stop (
63
) extends from the second end of each of the wing plates (
600
). The stop (
63
) has a slot (
631
) defined near the middle portion of the stop (
63
). A guide slot (
64
) is defined in each of the wing plates (
600
) between the through hole (
61
) and the pivot hole (
62
). The guide slot (
64
) is aligned with a radius of the pivot hole (
62
) in the corresponding wing plate (
50
) and an extended diameter of the hole (
604
) in the retaining plate (
602
) that is perpendicular to both wing plates (
600
). A brake pawl (
65
) has two opposite sides respectively sliding in the guide slots (
64
) and a stub (
651
) extending through the hole (
604
) in the retaining plate (
602
). A spring (
652
) is mounted around the stub (
651
) of the brake pawl (
65
) between the brake pawl (
65
) and the retaining plate (
602
) to push the brake pawl (
65
) toward the pivot hole (
62
).
The lever (
70
) has a distal end and a proximal end and includes two side plates (
71
) perpendicular to and integrally formed with a connecting plate (
72
) at the distal end. A retaining plate (
74
) extends perpendicular from the connecting plate (
72
) and has a through hole (
741
) defined in the retaining plate (
74
). The internal width of the two side plates (
71
) is greater than the external width of the two wing plates (
600
) such that a gap is formed between the corresponding side plates (
71
) and wing plates (
600
). A pivot hole (not shown) is defined in a proximal end of the side plates (
71
) and corresponds to the pivot hole (
62
) in the seat (
60
). The diameter of the pivot hole in the lever (
70
) is the same as the diameter of the pivot hole (
62
) in the seat (
60
). A cam (
73
) extends from the proximal end of the side plate (
71
) to push the brake pawl (
65
). A guide slot (
711
) is defined in the side plate (
71
) aligned with the center of the pivot hole in the side plate (
71
) and an extended diameter of the through hole (
741
) in the retaining plate (
74
) perpendicular to the side plates (
71
).
Two ratchet wheels (
81
) are respectively mounted in the gaps between the two side plates (
71
) and the two wing plates (
600
). A pivot pin (
80
) extends through the pivot hole in the lever (
70
), the pivot hole (
62
) in the wing plate (
600
) and the two ratchet wheels (
81
) to attach the lever (
70
) and the two ratchet wheels (
81
) to the seat (
60
). The pivot pin (
80
) includes two half-round bars (
801
), and each of the ratchet wheels (
81
) has two half-round holes (not shown) defined to correspond to each other and allow the half-round bar (
801
) to extend through corresponding half-round holes. Consequently, the pivot pin (
80
) is rotated by the two ratchet wheels (
81
) when the lever (
70
) is pivoted. The ratchet wheel (
81
) includes multiple teeth each having a sliding side and a limiting side. The limiting side engages with the brake pawl (
65
) so that the ratchet wheel (
81
) rotates only in the direction from the brake pawl (
65
) to the lever (
70
). The pivot pin (
80
) includes two opposite ends. A locking hole (
802
) is defined in each end to receive a locking pin (
82
) that is secured on the pivot pin (
80
) to prevent the pivot pin (
80
) from detaching from the seat (
60
) and the lever (
70
).
To operate the strap tightener, the ratchet wheel (
81
) is stopped by the brake pawl (
65
) when the lever (
70
) is pivoted toward the hook (
500
). A drive pawl (
75
) has two opposite sides sliding in the guide slot (
711
) in the side plate (
71
) of the lever (
70
). A stub (
751
) extends through the through hole (
741
) in the retaining plate (
74
) on the lever (
70
) from the drive pawl (
75
). A spring (
752
) is mounted around the stub (
751
) and between the drive pawl (
75
) and the retaining plate (
74
) to push the drive pawl (
75
) to engage with the ratchet wheel (
81
). The ratchet wheel (
81
) is rotated to drive the pivot pin (
80
) to roll the strap (
100
) when the lever (
70
) is pivoted away from the hook (
500
).
To release the tension on the strap, the lever (
70
) is moved outward relative to the hook (
500
) and the drive pawl (
75
) is moved to abut the stop (
63
). Then the user must press the drive pawl (
75
) toward the distal end of the lever (
70
) and simultaneously move the lever (
70
) until the end of the drive pawl (
75
) is received in the slot (
631
) in the stop (
63
). At the same time, the cam (
73
) in the lever (
70
) presses the brake pawl (
65
) away from the ratchet wheel (
81
) to release the ratchet wheel (
81
). With neither the brake pawl (
65
) nor the drive pawl (
75
) engaging the ratchet wheel (
81
), the user can pull the strap (
100
) through the strap tenser.
With reference to
FIG. 6
, the spring (
652
) pushes the brake pawl (
65
), and the brake pawl (
65
) actuates the cam (
73
) on the lever (
70
). The spring (
752
) pushes the drive pawl (
75
) and the drive pawl (
75
) actuates the stop (
63
) on the seat (
60
). Consequently, a shearing force formed by the lever (
70
) and the seat (
60
) due to the restitution force of the springs (
652
,
752
) actuates the pivot pin (
80
) so that the friction between the seat (
60
) and the lever (
70
) and the pivot pin (
80
) is raised. The increased friction may shorten the useful life of the strap tightener.
The present invention has arisen to mitigate and/or obviate the disadvantages of the conventional strap tightener.
SUMMARY OF THE INVENTION
The main objective of the present invent

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