Mobility restraint device tensioner

Abstract

A tensioning device is provided for tensioning a retractor in a wheelchair securement system. The tensioning device may include a clutch assembly for communicating rotational movement of a handle to a drive shaft operably connected to the spool of the retractor. The clutch assembly may include a pawl operably connected to the handle, which pawl communicates rotational movement of the handle to a drive sprocket. The clutch assembly may also include a friction member which communicates rotation of the drive sprocket to the drive shaft up to a predetermined amount of rotational force. If the rotational force exceeds the predetermined amount, the friction member will slip and cease to transfer rotational movement from the drive sprocket to the drive shaft. The clutch assembly may also include a compression member for compressing the friction member and drive sprocket whereby the predetermined amount of force may be adjusted.

Claims

1. A tensioning device comprising a handle operably connected to a drive shaft by a clutch assembly wherein rotational movement of the handle is communicated to the drive shaft by the clutch assembly until the clutch assembly reaches a preset torque limit wherein: at least one retractor is rotationally operable by the drive shaft, the retractor having a strap with a first end wound in the retractor and a second end extending from the retractor; the clutch assembly comprises at least one friction disc, a pawl, and a drive sprocket; the pawl is operably connected to the handle and communicates rotational movement of the handle to the drive sprocket; and, the friction member communicates rotation of the drive sprocket to the drive shaft up to the preset torque limit; and, the retractor includes a locked mode where a retractor pawl engages a retractor sprocket whereby the strap can be retracted but not withdrawn from a retractor spool.

2. A tensioning device comprising a handle operably connected to a drive shaft by a clutch assembly wherein rotational movement of the handle is communicated to the drive shaft by the clutch assembly until the clutch assembly reaches a preset torque limit wherein: at least one retractor is rotationally operable by the drive shaft, the retractor having a strap with a first end wound in the retractor and a second end extending from the retractor; the clutch assembly comprises at least one friction member, a pawl, and a drive sprocket; the pawl is operably connected to the handle and communicates rotational movement of the handle to the drive sprocket; and, the friction member communicates rotation of the drive sprocket to the drive shaft up to the preset torque limit; and, the retractor includes a locked mode where a retractor pawl engages a retractor sprocket whereby the strap can be retracted but not withdrawn from a retractor spool; wherein the drive shaft is directly connected to a shaft of the retractor.

3. A tensioning device comprising a handle operably connected to a drive shaft by a clutch assembly wherein rotational movement of the handle is communicated to the drive shaft by the clutch assembly until the clutch assembly reaches a preset torque limit wherein: at least one retractor is rotationally operable by the drive shaft, the retractor having a strap with a first end wound in the retractor and a second end extending from the retractor; the clutch assembly comprises at least one friction member, a pawl, and a drive sprocket; the pawl is operably connected to the handle and communicates rotational movement of the handle to the drive sprocket; and, the friction member communicates rotation of the drive sprocket to the drive shaft up to the preset torque limit; and, the retractor includes a locked mode where a retractor pawl engages a retractor sprocket whereby the strap can be retracted but not withdrawn from a retractor spool; wherein the clutch assembly further comprises a compression member for compressing the friction member between the drive member and the drive shaft.

4. The tensioning device of claim 3 wherein the compression member is adjustable, whereby the preset torque limit can be changed by adjusting the compression member.

5. The tensioning device of claim 1, wherein: the tensioning device has two modes; the tensioning device further includes a hub with a condition indicator, the hub being rotationally biased to display the condition indicator; the handle urging the hub to substantially obscure the condition indicator from all observable angles when placed in one of the two modes.

6. The tensioning device of claim 5, wherein the hub is rotationally connected to a retractor release member that engages a retractor pawl release arm when the tensioning device is in one of the two modes.

7. The tensioning device of claim 1, wherein: the tensioning device has a stow mode and a tension mode; the tensioning device further includes a hub with a safe condition indicator and a non-safe condition indicator, the hub being rotationally biased to display the safe condition indicator; and, in the stow mode, the handle urging the hub to display the unsafe condition indicator.

8. The tensioning device of claim 7, wherein the hub is rotationally connected to a retractor release member that engages a retractor pawl release arm when the tensioning device is in the stow mode.

9. The tensioning device of claim 1, wherein: the tensioning device has a stow mode and a tension mode; the tensioning device further includes a retractor release member that is rotationally biased out of engagement with a pawl release arm of the retractor; and, in the stow position, the handle urging the retractor release member into engagement with the pawl release arm.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) These and other features, aspects, objects, and advantages of the embodiments described and claimed herein will become better understood upon consideration of the following detailed description, appended claims, and accompanying drawings.

(2) FIG. 1 is a perspective view of a first embodiment of a tensioner;

(3) FIG. 2 is a second perspective view of the first embodiment showing the clutch mechanism;

(4) FIG. 3 is a third perspective view of the first embodiment showing additional components of the clutch mechanism;

(5) FIG. 4 is an exploded view of the clutch mechanism for the first embodiment;

(6) FIG. 5 is first side view of the first embodiment showing the release button mechanism in the stow mode;

(7) FIG. 6 is a fourth perspective view of the first embodiment showing internal components of the release button mechanism in the stow mode;

(8) FIG. 7 is a second side view of the first embodiment showing the release button mechanism in transition from the stow mode to the tension mode;

(9) FIG. 8 is third side view of the first embodiment showing the release button mechanism in the tension mode;

(10) FIG. 9 is a fourth side view of the first embodiment showing the safety indication mechanism in the stow mode;

(11) FIG. 10 a fifth perspective view of the first embodiment showing the safety indication mechanism in the stow mode;

(12) FIG. 11 is a first side view of a second embodiment of a tensioner in the stow mode;

(13) FIG. 12 is a first front view of the second embodiment in the stow mode;

(14) FIG. 13 is a second side view of the second embodiment in the tension mode;

(15) FIG. 14 is a second front view of the second embodiment in the tension mode;

(16) FIG. 15 is a first perspective view of the second embodiment showing the clutch mechanism; and,

(17) FIG. 16 is a second perspective view of the second embodiment showing the safety indication mechanism.

(18) It should be understood that the drawings are not necessarily to scale and that the embodiments are sometimes illustrated by graphic symbols, phantom lines, diagrammatic representations and fragmentary views. In certain instances, details which are not necessary for an understanding of the embodiments described and claimed herein or which render other details difficult to perceive may have been omitted. It should be understood, of course, that the inventions described herein are not necessarily limited to the particular embodiments illustrated. Indeed, it is expected that persons of ordinary skill in the art may devise a number of alternative configurations that are similar and equivalent to the embodiments shown and described herein without departing from the spirit and scope of the claims.

(19) Like reference numerals will be used to refer to like or similar parts from Figure to Figure in the following detailed description of the drawings.

DETAILED DESCRIPTION OF THE PRESENT EMBODIMENTS

(20) With reference to FIGS. 1-4, a first embodiment of a tensioner 1 and an associated clutch (or clutch assembly/mechanism) 200 is shown. The clutch assembly 200 is an automatic load limiting device that limits the torque applied to the connector shaft 300 by slipping of the drive sprocket 260 with respect to the drive hub 270. The range of torque is adjustable by the hex nut (compression member) 220 which applies a load of force to the friction discs (friction members) 210 thru the pressure plate 250. The frictional force couples the drive sprocket (drive member) 260 to the hub 270 which is connected to the drive shaft 300. As the handle 100 is rotated, the drive pawl 110 engages the drive sprocket 260 which causes the connector shaft 300 to rotate. Since the connector shaft 300 is coupled to the retractor 400 shaft, it will also rotate causing the webbing 410 to be wound into the retractor 400. As the webbing 410 is being wound into the retractor 400 while the end (not shown) is connected to a mobility device (not shown), a tension load develops on the webbing 410. As the web 410 load increases, the torque demand also increases until it is greater than the preset torque on the clutch 200 causing a slip between the sprocket 260 and friction discs 210. At this point, because the inner surface 265 of the sprocket 260 is not mechanically coupled to the hub 270 and can freely rotate relative to the hub 270, no additional torque can be applied and therefore no additional tension load on the web 410 can be achievedthe clutch 200 will just keep slipping.

(21) FIGS. 5-8 depict a release button mechanism for the first embodiment of the tensioner 1, which is operated by the release button at the top of the handle. When the handle 100 is in the stow position, as shown in FIGS. 5-6, the push cam 130 is in the up position and the lock/release arm 140 is in the first lock slot 150. At this point, the ratchet pawl 110 is held away from the clutch sprocket 260 by the control plate 170. At the same time, the retractor release shaft (retractor release member) 160 engages and pushes down the retractor pawl release arm 420, placing the retractor 400 in an unlocked state (allowing webbing 410 to be retracted and withdrawn).

(22) FIG. 7 shows the release button mechanism in transition from the stow mode to the tension mode, while FIG. 8 shows the release button mechanism in the tension mode. When the release button 120 is pressed down, as shown in FIG. 7, the push cam 130 moves down and the lock/release arm 140 moves out from the first lock slot 150. As the handle 100 rotates forward and the push button 120 is released, as shown in FIG. 8, the push cam 130 moves up and the lock/release arm 140 engages the second lock slot 155. At this point, the retractor release shaft 160 moves up and out of engagement with the retractor pawl release arm 420. In that regard, the retractor 400 is placed in a locked mode where the retractor pawl 430 engages the retractor sprocket 440 (whereby webbing 410 can be retracted, but not withdrawn from the retractor spool 450). The ratchet pawl 110 engages the clutch 200, as shown in both FIGS. 7 and 8, and as the handle 100 is moved up and down tension is applied to the retractor 400 web 410.

(23) FIGS. 9 and 10 show the operation of the safety indication mechanism of the first embodiment. When the handle 100 is in the stowed/release position (FIGS. 9 and 10), the retractor release shaft 160 is pushed down in the control plate slot 175 causing the lock indicator 180 to move up indicating that the handle 100 is in the stowed released position. When the handle 100 is moved to the lock/tension mode, the lock indicator 180 will move down as the lock indicator bracket 190 is spring loaded (i.e., forcing the retractor release shaft 160 upward into engagement with the top of the control plate slot 175).

(24) With reference to Figures to 11 to 16, a second embodiment of the tensioner 1001 is shown. FIGS. 11-12 show the tensioner 1001 in the Stow Mode, while FIGS. 13-14 show the tensioner 1001 in the Tension Mode. The safety indicator window 1180 reflects a released condition, as shown in FIG. 12, when the tensioner 1001 is in the Stow Mode. In large part, the clutch mechanism 1200 of the second embodiment is the same as that of the first embodiment. One major difference between the first and second embodiment relates to the release button mechanism. The second embodiment, as shown in FIG. 15, does not include a push button, but rather includes a trigger 1120 on the underside of the handle 1100. Squeezing the of the trigger 1120 lifts the lock member 1140, by way of a cable or similar component (not shown), out of a first lock slot 1150 in the control plate 1170, which allows the handle 1100 to be moved from the Stow Mode to the Tension Mode. Once the trigger 1120 is released, the lock member 1140 moves downward due to biasing by a spring (not shown) or the like. The lip 1155 in the control plate prohibits the handle 1100 from moving back to the Stow Mode until the trigger 1120 is squeezed such that the lock member 1140 lifts to clear the lip 1155.

(25) Another slight difference between the first and second embodiment is the lock indicator bracket 1190, which is shown in FIG. 16. As before, the lock indicator bracket 1190 is held in the position shown in FIG. 16 by the handle 1100. When the handle 1100 is moved to the Tension Mode, the lock indicator bracket 1190 is biased in a counter-clockwise direction (view from the angle shown in FIG. 27) such that the release indicator 1185 is not visible through the indicator window 1180.

(26) Although the inventions described and claimed herein have been described in considerable detail with reference to certain embodiments, one skilled in the art will appreciate that the inventions described and claimed herein can be practiced by other than those embodiments, which have been presented for purposes of illustration and not of limitation. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.