GB1568763A - Safety belt tensioning and rewingding retractor - Google Patents

Description

(54) SAFETY BELTS TENSIONING AND REWINDING RETRACTOR (71) We, AMERICAN SAFETY EQUIPMENT CORPORATION, A corporation organized and existing under the laws of the State of New York, United States of America, of 16055 Ventura Boulevard, Encino, California 91436, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following state ment: - This invention relates in general to safety belt tensioning and rewinding means for retractors employed in storing safety belts of safety harnesses utilized in vehicles for restraining a passenger in his seat during emergency conditions and more specifically, to such means for applying a lower tension on the safety belt when unwound to a position to use than normally applied to rewind the belt.

Emergency locking retractors normally used in safety harness systems employed in vehicles currently are of the emergency locking type, i.e. the retractor locks against further belt un-winding or protraction only in the event of an emergency condition which may be sensed due to strap acceleration as the persons body moves forward pulling the strap out of the retractor or in response to changes in vehicle acceleration sensed by an inertia sensor or mass associated with the retractor. In such emergency locking retractors, the seat belt webbing or belt is free to move in and out under normal occupant movement subject to the rewind bias of the retractor rewind spring. Tension applied to the belt by virtue of the bias of the rewind spring required for rewinding long lengths of webbing or safety belt employed in safety harness systems can be objectionable to the user. Thereto, various arrangements have been made heretofore for reducing the tension applied to the belt by the rewind spring when the belt is placed in use. We have found it to be desirable to provide a safety belt tensioning and rewinding retractor wherein the low tensioning and rewinding means may be provided in a more compact retractor construction and wherein a second biasing means operates in a novel and more fascile manner in association with the belt storage reel and a first biasing means than those of prior attempts.

In accordance with the present invention there is provided a safety belt retractor comprising a frame. a safety belt storage reel rotatably mounted on the frame, emergency means actuable to lock the reel against rotation in an unwinding direction, a member rotatably mounted to said frame and rotatable relative to the reel, means for limiting rotation of the member in a first direction, first spring means arranged to act between said member and reel for biasing said member rotationally in said first direction and said reel in an opposite, belt rewinding direction, means operable to connect said member to said reel to prevent relative rotation therebetween under the action of the first spring means, and thereby block the bias of said first spring means, in response to rotation of the reel in a belt rewind direction following rotation thereof in a belt unwind direction. and second spring means for biasing said member in such a direction that when said reel is connected to said member by said connecting means, the reel is biased in a rewind direction by said second spring means.

The invention also provides a safety belt retractor comprising a safety belt storage reel, and first spring means for biasing said reel in a belt rewind direction, second spring means actuable to provide a reduced rewind bias on said reel, means for activating said second spring means in response to reel rotation in a predetermined manner, and means for deactivating said second spring means in response to reel rotation, in a belt rewind direction, of more than one full revolution while the second spring means is activated, the deactivating means including a spiral cam surface and a cam follower arranged to be driven along the cam surface by rotation of said reel when the second means is activated.

A better understanding of the invention will be had from the following detailed description given by way of example with reference to the accompanying drawings, in which: Figure 1 is a plan view of a safety belt retractor in accordance with the present invention; Figure 2 is a side view of the retractor of Figure 1 taken along the plane II-II showing the retractor in a comfort zone mode; Figure 3 is a section view of the retractor of Figure 2 taken therein along the plane III-III; Figure 4 is a view of the retractor as in Figure 2 showing the retractor in a belt unwinding mode; Figure 5 is a view of the retractor as in Figure 2 showing the retractor in a belt rewinding mode; Figure 6 is a section view of the retractor of Figure 2 taken therein along the plane VI-VI; Figure 7 is a section view of the retractor of Figure 4 taken therein along the plane VIl-VIl; Figure 8 is a detail section view of a portion of the retractor of Figure 5 taken therein along the plane VIII-VIII; Figure 9 is a side elevational view as in Figure 2 showing an alternative construction of safety belt tensioning and rewinding retractor means in a comfort zone mode; Figure 10 is a section view of the retractor of Figure 9 taken therein along the plane X-X; Figure 11 is a view of the retractor as in Figure 9 showing a belt unwinding mode; Figure 12 is a view of the retractor as in Figure 9 showing a belt rewinding mode; Figure 13 is a detail section view of the retractor of Figure 11 take therein along the plane XIIl-XIII, and Figure 14 is a detail section view of the retractor of Figure 11 taken therein along the plane XIV-XIV Figure 15 is a plan view of another exemplary embodiment of emergency locking retractor employing the improvements in an extended low tension range dual tension safety belt retractor in accordance with the present invention; Figure 16 is a section view of the retractor of Figure 18 taken along the plane XVI XVI; Figure 17 is a side section view of the retractor of Figure 18 showing the improvement in extended low tension range dual tensioning means of the present invention; Figure 18 is a cross-section view taken along the plane XVII-XVII in Figure 17; Figure 19 is a detailed view, partially in section, taken along the plane XVII-XVII in Figure 17; Figure 20 is a detailed view of portions of the dual tension means of Figure 17 and 18 shown in exploded relation; Figure 21 is a detailed view of the dual tension means of Figure 17 showing the means in a low tension mode; Figure 22 is a detailed view as in Figure 21 showing release of the dual tension means from the low tension mode of Figures 17 and 21; and Figure 23 is a detailed view as in Figure 20 showing the illustrated parts in assembled relation.

Referring initially to Figure 1, the retractor indicated generally 10, as is conventional in emergency locking retractors, includes a generally U-shaped frame 11 having base 12 and side walls 13 and 14. Safety belt 15, which may be part of a safetly harness or belt system as known in the industry, is wound upon the reel. indicated generally at 16. of the retractor as best seen in Figures 2 and 3. The reel includes a pair of spaced ratchet wheels 17 and 18 fixed upon shaft 21 which in turn is mounted by bushings. as bushing 20, to the retractor frame side walls 17 and 18. Spool 19 is fixed to ratchet wheels 17 and 18 in conventional manner.

Emergency locking means are provided in the exemplary retractor as indicated generally at 25. Such means, in the exemplary embodiment, includes a locking pawl bar 26 pivotally mounted between frame side walls 13 and 14 for engagement with the respective ratchet wheels 17 and 18 on tilting movement of bar 26. A pendulum-like inertia sensor mass 27 is suspended from support bar 28 to place a head portion thereof beneath bar 26 to cause tilting movement of bar 26, to lock the retractor against further belt unwinding on swinging movement of pendulum 27, as during a deceleration of the vehicle in an emergency situation. The retractor construction explained thus far is considered conventional.

As is particularly contemplated within the present invention. safety belt tensioning and rewind means are provided for normally causing belt 15 to be rewound into a stored condition on reel 16, and. importantly, to provide for a reduced tension effect on belt 15 when placed in use by an occupant of a vehicle in which the retractor is utilized. An exemplary safety belt tensioning and rewinding means, in accordance with the present invention is indicated generally at 3() in Figure 1 within housing 31 which includes an upper generally cylindrical por tion 32 and a lower, laterally disposed, smaller generally cylindrical portion 33. As seen in Figures 2 and 3, housing 31 includes a base 34 by which the housing is mounted to frame side wall 13 and retained there via suitable fasteners, as fasteners, 35, 36 and 37, which in the exemplary embodiment may include head bolts threaded through base 34 into retractor side wall 13. As best seen in Figure 2, a port 38 allows communication between the two housing portions 32 and 33 for purposes as will become apparent subsequently.

First biasing means for biasing the safety belt reel 16 toward a belt storage condition is provided within housing portion 32. In the exemplary embodiment, such first biasing means comprises a main rewind spring 40 which is of coil configuration having its inner end 41 connected to shaft 21 via slot 23. An outer end 42, as seen in Figure 2, is connected to member 50 whose function will be described subsequently.

As best seen in Figures 2 and 3, member 50 is rotatably mounted relative to shaft 21, and, in the exemplary embodiment, is of drum-like configuration having a cylindrical outer wall 51 provided with a slot 52 which receives the outer end 42 of the rewind spring 40. Drum member 50 is further provided with a cylindrical web 53 which has a central aperture mounted upon and rotatable relative to an inner bushing portion 54 of bushing 55 which is fixed via web 56 in non-rotatable relation to shaft 21.

From the foregoing, it can be seen that spring 40 normally biases member 50 in a clockwise direction and shaft 21 in a counterclockwise, webbing rewind, direction in Figures 2, 4 and 5. However, in accordance with the present invention, means are provided for limiting the clockwise rotation of member 50 such means in the exemplary embodiment, including the provision of bumper 57 upon web of member 50 and a co-operating stop or abutment 58 formed integrally of housing 31. Stop or abutment 58 is provided with a resilient stop member 59 against which bumper 57 may abut, as seem in Figure 4, to limit clockwise rotation of member 50 during an unwinding of belt 15 off reel 16 against the bias of main spring 40.

In accordance with the present invention.

means are provided for releasably connecting member 50 to reel 16 to block the bias of rewind spring 40, and thus relieve belt 15 of tension due to spring bias, when belt 15 has been unwound to a position of use. Such connecting means in the exemplary embodiment is indicated generally at 60 and includes the provision of pawl 61 mounted by mounting pin 62 for pivotal movement on web 53 of member 50. A ratchet 63 of wheel or gear-like configuration is formed integrally of bushing 55, as seen in Figures 2 and 3, with teeth 64 facing in a counterclockwise direction in Figure 2 for engagement by pawl tooth 65 as seen in Figure 2. When pawl 61 engages ratchet 63 as seen in Figure 2, member 50 is thus connected to shaft 21 and reel 16 in a manner preventing relative rotation due to the bias of main spring 40.

The connecting means indicated generally at 60 may thus be considered a means for blocking out the bias of the first biasing means, according to the present invention, which in the exemplary embodiment comprises coil spring 40.

The operation of pawl 61 between engagements and disengagements with ratchet 63, as will be explained more fully hereinafter, is in part controlled by a spring wire combination clutch and cam means 70 which has a circular body portion mounted in groove 71 of member 55 to provide a frictionally driven relation to cam means 70 in response to rotation of reel 16. Combination clutch and cam means 70 is further provided with cam arm portions 72 and 73, as seen in Figure 2, for engaging cam follower pin 66 provided on pawl 61. During a normal unwinding operation of reel 16, as seen in Figure 4, cam arm 72 will move cam follower pin 66 to the position shown in Figure 4 holding pawl 61 out of engagement with ratchet 63 and thus allowing the rewind bias of main spring 40 to be applied to belt 15 as belt 15 is unwound from the reel 16.

However, on a slight rewinding movement of belt 15, as normally occurs during buckling up of a safety belt harness employing a safety belt as belt 15, the reel will move in a rewind direction from the position of Figure 4 toward the position of Figure 2 causing cam arm 72 to relieve cam follower pin 66 and allow pawl 61 to fall into engagement with ratchet 63. Such engagement occurs with bumper 57 still engaging member 59 of stop 58 with subsequent movement of member 50 and reel 16 in a counterclockwise direction from the position of Figure 4 to the position of Figure 2 being under the urging of the second biasing means in accordance with the present invention as will now be explained.

A reduced tension effect is provided in the exemplary embodiment of retractor when the bias of the aforedescribed first biasing means is blocked out through the interconnection of member 50 and reel 16 and in the present exemplary embodiment, comprises the provision of a second biasing means in a manner hereafter explained for biasing member 50 in a belt rewind direction whereby reel 16, when so connected to member 50. is biased in a rewind direction by a lower biasing effect of such second biasing means. Referring to Figures 2 and 3, in the exemplary embodiment, such second biasing means is indicated generally at 80 and includes a constant torque spring 81 of coil configuration with its main body portion positioned loosely within the laterally disposed smaller housing portion 33 with an inner end 82 merely left free. As particularly contemplated within the present invention, the second spring means 81 is positioned laterally of first spring 40 with their axes parallel and spaced laterally of one another in a direction normal to the axis of the reel shaft 21. This construction allows the positioning of the two spring means in a flatter or narrower housing mounted to the side wall 13 as is deemed desirable for such retractors which are to be fitted into fairly small or compact locations in a vehicle in which the retractor is to be utilized. As further seen in Figures 2 and 3, second spring 81 is of serpentine configuration in that it winds from housing portion 33 through port 38 and into the larger housing portion 32 where its outer end 84 is secured to member 50 via slot 85 with outer end portions 86 of spring 81 encircling member 50 when member 50 is in the position as seen in Figure 4 during belt unwinding. The bias of second spring 81 is thus in a counterclockwise direction in figures 2 and 4, a direction opposite to the bias of first spring 40 on member 50.

As should be apparent from the foregoing, during an initial belt unwinding of belt 15 to a location of use, the retractor mode is as illustrated in Figure 4 with member 50 being restricted in its clockwise rotation due to the engagement of bumper 57 with stop member 59, second spring 81 having been unwound against its bias and main spring 40 tending to cause rewind of reel 16. On a slight rewind movement of belt 15, cam means 70 release pawl 61 as aforedescribed to allow pawl 61 to move from the position of Figure 4 to a position engaging ratchet 63 as seen in Figure 2.

With the bias of main spring 40 thus blocked, the retractor is placed in a 'low tension zone" or lower tension bias bv the action of the smaller coil spring 81 which tends to move member 50 and interconnected reel 16 in a lower tension rewind direction as illustrated in Figure 2 toward the pawl release position of Figure 5. When the position of Figure 5 is reached. the pawl 61 is relesed, as subsequently described, allowing for a rewind belt 15 under the bias of main spring 40.

When the exemplary retractor is in the "low tension" mode as seen in Figure 2. the lower tensioning effect on belt 15 due to the lower bias of spring 81 maintains the seat belt 15 snug against the users body. which would be the chest when belt is part of typical vehicle safety harness of the three point emergency locking type currently in use. Such reduced tensioning of belt 15 will continue in the retractor construction of the current embodiment for up to nearly a full revolution of reel 16 in a counterclockwise direction from the position of Figure 2 to the position of Figure 5. Cam means, indicated generally at 75, are mounted to the retractor frame to be engaged by a portion of pawl 61 upon rotation of member 50 to the position of Figure 5 in order to release pawl 61 from engagement with ratchet 63. As seen in Figures 2, 4 and 5, the cam means indicated generally at 75 comprises an arcuate body 76 having an inwardly facing cam surface 77 which is engaged by the cam follower rear end portion 67 of pawl 61. Cam surface 77 progresses radially inwardly from its leading end 78 in a counterclockwise direction in Figure 5 so that cam follower portion 67 pivots pawl 61 out of engagement with ratchet teeth 64 by the time member 50 has rotated to almost a full counter revolution as seen in Figure 5. A recess 68 is preferably provided in the rear end of pawl 61 to provide a surface to abut against limit member 69 which prevents over pivoting of pawl 61. As is preferred in accordance with the present invention, cam means 75 and bumper stop 58 are formed integrally of each other and of housing 31.

On release of pawl 61 from ratchet 63, the stronger rewind bias of spring 40 will cause an unwinding of smaller spring 81 to bring member 50 back to the position of Figure 4 and to allow rewinding of webbing 15 under the strong rewind bias of spring 40. Specifically as seen in Figure 5, when pawl 61 is released from ratchet 63 spring 40 tends to turn bushing 55 counterclockwise and member 50 clockwise causing cam arm 73 to engage cam pin 68. As member 50 returns to the position of Figure 4, combination clutch and cam means 70 is returned, via the engagement between pawl pin 68 and cam arm 73, as well where it will continue to hold pawl 61 unlocked from ratchet 63 during a continuing full rewind of webbing 15 on reel 16. Subsequently, on pulling of belt 15 outwardly of the retractor. clutch and cam means 70 will move to the position of Figure 4 to hold pawl 61 unlocked until there is a subsequent slight retractive movement of belt 15 as seen in Figure 2.

An alternative exemplary embodiment of safety belt tensioning and rewind retractor in accordance with the present invention is shown in Figures 9 through 14. Referring first to Figures 9 and 10, the retractor indicated generally at 110 may, as with the retractor indicated generally at 10 in Figure 1, employ a retractor frame having a side wall 113 mounting a reel indicated generally at 116 on a shaft 121 which is journaled by suitable bushings, as bushing 120 to the retractor side walls. The reel, indicated generally at 116, as before, includes a pair of ratchet wheels, as ratchet wheel 118 supporting spool 119.

Housing 131, in this embodiment, as before, includes an upper cylindrical portion 132 and a smaller lower or laterally disposed cylindrical portion 133 mounted by base 134 and suitable fasteners 135, 136 and 137 to side wall 113. A port 138 is formed in the housing betwen portions 132 and 133.

The first biasing means in the alternative exemplary embodiment includes, as before a first coil spring 140 having an inner end 141 connected to shaft 121 via slot 123 and an outer end 142 fastened by fastening means 143 to the surrounding cylindrical portion 151 of member 150. Member 150 is mounted on bushing 155 via web portion 153, member 155 being fixed by its web 156 to shaft 21 and member 150 being rotatable on member 155. However, as is particularly contemplated within the invention of the alternative exemplary embodiment, member 150 is provided with a plurality of gear teeth 190 about its periphery. Bumper 157 is formed integrally of member 150 and is provided with a resilient member 159 in its socket as seen in Figure 9. Cam means 175 is formed integrally of stop or abutment 158 and housing 131 as in the preferred exemplary embodiment, but abutment 158 is of a generally circular or blunt ended configuration as seen in Figure 9. The provision of resilient member 159 accomplished a desired reduction of noise in operation of the retractor.

The construction of pawl 161, pivotally mounted on pin 162 with the pawl tooth 165 for engagement with ratchet 163 is essentially the same as in the preferred exemplary embodiment aforedescribed. A combination clutch and cam means 170 is also provided as before. However, the configuration of pawl 161 at its rear end is slightly different with the rear end merely comprising a tapering extension 167 adapted to co-operate between cam surface 176 and limit member 169 during operation of the pawl and ratchet means as in the prior embodiment.

As is particularly contemplated within the present invention as expressed in the alternative exemplarly embodiment, the second biasing means indicated generally at 180, includes a coil spring 181 having an inner end 182 fixed to a pin 183, with its outer end 184 being connected to a surrounding outer gear member 191 having gear teeth 192.

Outer gear member 191 is positioned within housing 133 about spring 181 with its teeth 192 meshing with the teeth 190 provided on drum member 150 to provide a gear drive between the second spring 181 and member 50.

As will be apparent from the foregoing, the retractor of the alternative exemplary embodiment will operate generally in the same manner as that of the preferred exemplary embodiment described hereinbefore, but the second biasing means, comprising spring 181, is connected by a gear drive member 150 as opposed to the serpentine configuration and encircling connection of spring end 84 with member 50 employed for spring 81 of the preferred exemplary embodiment. The low tension effect of a reduced tension due to spring 81 may be provided as desired through the selection of the torque characteristics of the two springs 40 and 81 and/or varying the number of teeth provided for the gear teeth 190 on member 150 and gear teeth 192 on member 191. The mode of operation of the alternative exemplary retractor remains the same as that of the preferred exemplarly embodiment of Figures 4 through 8 as seen in Figures 11-14. On unwinding of belt 115, member 150 will tend to turn clockwise with its bumper 157 and resilient member 159 abutting stop 158 as seen in Figure 11. Pawl 161 is held unlocked by cam arm 172. On a slight belt rewind movement of reel 116, as seen in Figure 9, pawl 161 is released and falls into locking engagement with ratchet 163. A low tension zone effect is then provided under the lower tension of spring 181 for the extent of belt travel allowed by reel movement from the position of Figure 9 to the pawl release position of Figure 12.

The main spring is reactivated by protraction or retraction of belt 15 beyond the limits of such low tension belt movement.

An alternative means for disengaging member 50 from reel 16. by releasing pawl 61 from ratchet 63 of the first exemplary embodiment herein is illustrated in Figures 15-23. Referring to Figures 15-23, the retractor construction of Figures 1-8 is shown, with like parts having like reference numbers plus two hundred. i.e. frame 11 in Figure 1 is frame 211 in Figure 15, except as stated hereinafter.

As is particularly contemplated within the present exemplary embodiment of the invention, the range of reel rotation under the bias of the second low tension biasing of spring 281 is extended fro more than one full reel rotation before the means for relieving the tension of the main rewind spring 240 is deactivated. In the exemplary embodiment, such means include the provision of spiral cam surface means, indicated generally at 290. formed on an inner surface of housing 231 and thereby mounted to frame 211. As best seen in Figure 16, the exemplary spiral cam surface is provided by a spiral groove 291 having an extent of more than one full revolution about its spiral center. The spiral groove in the exemplary embodiment extends from an inner end 292 to an outwardly diverging spiral path including outer surface portions 293 spaced radially outwardly relative center to an outer end 294.

The main spring tension relieving means, pawl 261 and ratchet 263 in the exemplary embodiment, are deactivated in accordance with the present invention through operation of cam actuated means for moving pawl 261 out of engagement with ratchet 263 after the reel has rotated in a rewind direction under the low tension of spring 281 of more than one full revolution. Referring to Figures 17 and 21, cam arm 275 is pivotally mounted to pin 262 and mounts a cam follower 276 for movement along surface 291. When pawl 261 engages ratchet 263, member 250, mounting pin 262, and the reel rotate in unison thus moving cam follower 276 under the driving action of arm 275 in unison with reel rotation in the low tension mode.

As best seen in Figure 20, the exemplary pawl 261 is mounted to pin 262 via a bifurcate mounting end including flanges 267 and 268. Arm 275 is provided with a flange 277 sized to fit between flanges 267 and 268 so that all three flanges are pivotally mounted about pin 262 as seen in Figure 23.

Cam arm 275 is further provided with an abutment surface 278 which abuts an underside of pawl 261, as seen in Figure 23, when arm 275 is pivoted about pin 262 relative to pawl 261 from the positions of Figures 17 and 21 to that of Figure 22.

As can be seen from the foregoing, as reel 216 rotates counter-clock-wise in Figure 17 under the urging of low tension spring 281, pawl follower 276 rides in the spiral groove along surface 293, moving radially inwardly as it progresses along the spiral groove as seen in Figure 21 until it reaches the inner end of the spiral groove, as seen in Figure 22, and raises pawl 261 out of engagement with ratchet 263 through the abutment of surface 278 with the underside of pawl 261.

On release of pawl 261 from ratchet 263, main rewind spring 240 becomes operable to bias member 250 in the clockwise direction and reel shaft 221 in the counter-clock-wise direction of Figures 17, 21 and 22. Drum 250 thus rotates from the position of Figure 22 back to that of Figure 17 where it is held through engagement of cam follower 276 with the end 294 of the spiral groove 291.

Rotation of member 250 in the clock-wise direction in Figure 17 is thus limited by the travel of cam follower 276 in spiral groove 291.

From the foregoing, it can be seen that the disengagement of pawl 261 from ratchet 263, to reactivate the main spring 240 is controlled by the radial displacement of cam follower 276 from the position of Figure 17 to that of Figure 22 whereby arm 275 places its abutment surface 278 into engagement with and lifts the pawl out of engagement with ratchet 263. As should be apparent to those skilled in the art, the length of spiral groove 291 may be selected as desired to provide for an extended range of the low tension mode, when pawl 261 is in engagement with ratchet 263, for as many turns of reel 216 as is desired by providing a comparable number of turns for the spiral cam surface indicated generally at 290. Attention is directed to our copending Application (Serial No. 1568764) 7901742 and (Serial No. 1568765) 7901743 in the complete specifications of which are described and claimed the retractors described herein with reference to Figures 1 to 14.

WHAT WE CLAIM IS: 1. A safety belt retractor comprising a frame, a safety belt storage reel rotatably mounted on the frame, emergency locking means actuable to lock the reel against rotation in an unwinding direction, a member rotatably mounted to said frame and rotatably relative to the reel, means for limiting rotation of the member in a first direction, first spring means arranged to act between said member and reel for biasing said member rotationally in said first direction and said reel in an opposite, belt rewinding direction, means operable to connect said member to said reel to prevent relative rotation therebetween under the action of the first spring means, and thereby block and bias of said first spring means, in response to rotation of the reel in a belt rewind direction following rotation thereof in a belt unwind direction, and second spring means for biasing said member in such a direction that when said reel is connected to said member by said connecting means, the reel is biased in a rewind direction by said second spring means.

2. A retractor as claimed in claim 1, wherein the bias exerted on the member by said second spring means is smaller than an opposite in direction to that exerted on the member bv said first spring means.

3. A retractor as

Claims (15)

**WARNING** start of CLMS field may overlap end of DESC **. diverging spiral path including outer surface portions 293 spaced radially outwardly relative center to an outer end 294. The main spring tension relieving means, pawl 261 and ratchet 263 in the exemplary embodiment, are deactivated in accordance with the present invention through operation of cam actuated means for moving pawl 261 out of engagement with ratchet 263 after the reel has rotated in a rewind direction under the low tension of spring 281 of more than one full revolution. Referring to Figures 17 and 21, cam arm 275 is pivotally mounted to pin 262 and mounts a cam follower 276 for movement along surface 291. When pawl 261 engages ratchet 263, member 250, mounting pin 262, and the reel rotate in unison thus moving cam follower 276 under the driving action of arm 275 in unison with reel rotation in the low tension mode. As best seen in Figure 20, the exemplary pawl 261 is mounted to pin 262 via a bifurcate mounting end including flanges 267 and 268. Arm 275 is provided with a flange 277 sized to fit between flanges 267 and 268 so that all three flanges are pivotally mounted about pin 262 as seen in Figure 23. Cam arm 275 is further provided with an abutment surface 278 which abuts an underside of pawl 261, as seen in Figure 23, when arm 275 is pivoted about pin 262 relative to pawl 261 from the positions of Figures 17 and 21 to that of Figure 22. As can be seen from the foregoing, as reel 216 rotates counter-clock-wise in Figure 17 under the urging of low tension spring 281, pawl follower 276 rides in the spiral groove along surface 293, moving radially inwardly as it progresses along the spiral groove as seen in Figure 21 until it reaches the inner end of the spiral groove, as seen in Figure 22, and raises pawl 261 out of engagement with ratchet 263 through the abutment of surface 278 with the underside of pawl 261. On release of pawl 261 from ratchet 263, main rewind spring 240 becomes operable to bias member 250 in the clockwise direction and reel shaft 221 in the counter-clock-wise direction of Figures 17, 21 and 22. Drum 250 thus rotates from the position of Figure 22 back to that of Figure 17 where it is held through engagement of cam follower 276 with the end 294 of the spiral groove 291. Rotation of member 250 in the clock-wise direction in Figure 17 is thus limited by the travel of cam follower 276 in spiral groove 291. From the foregoing, it can be seen that the disengagement of pawl 261 from ratchet 263, to reactivate the main spring 240 is controlled by the radial displacement of cam follower 276 from the position of Figure 17 to that of Figure 22 whereby arm 275 places its abutment surface 278 into engagement with and lifts the pawl out of engagement with ratchet 263. As should be apparent to those skilled in the art, the length of spiral groove 291 may be selected as desired to provide for an extended range of the low tension mode, when pawl 261 is in engagement with ratchet 263, for as many turns of reel 216 as is desired by providing a comparable number of turns for the spiral cam surface indicated generally at 290. Attention is directed to our copending Application (Serial No. 1568764) 7901742 and (Serial No. 1568765) 7901743 in the complete specifications of which are described and claimed the retractors described herein with reference to Figures 1 to 14. WHAT WE CLAIM IS:

1. A safety belt retractor comprising a frame, a safety belt storage reel rotatably mounted on the frame, emergency locking means actuable to lock the reel against rotation in an unwinding direction, a member rotatably mounted to said frame and rotatably relative to the reel, means for limiting rotation of the member in a first direction, first spring means arranged to act between said member and reel for biasing said member rotationally in said first direction and said reel in an opposite, belt rewinding direction, means operable to connect said member to said reel to prevent relative rotation therebetween under the action of the first spring means, and thereby block and bias of said first spring means, in response to rotation of the reel in a belt rewind direction following rotation thereof in a belt unwind direction, and second spring means for biasing said member in such a direction that when said reel is connected to said member by said connecting means, the reel is biased in a rewind direction by said second spring means.

2. A retractor as claimed in claim 1, wherein the bias exerted on the member by said second spring means is smaller than an opposite in direction to that exerted on the member bv said first spring means.

3. A retractor as claimed in claim 1 or 2, wherein said means operable to connect said member to said reel comprises ratchet and pawl means.

4. A retractor according to claim 3, wherein the ratchet and pawl means includes a pawl pivotally mounted on the member, and a ratchet rotatable with said reel and engageable by the pawl, and the retractor includes a spring wire combination clutch and cam means having a circular body portion mounted to be frictionally driven by the reel and oppositely directed cam arm portions for engaging said pawl to hold it disengaging from said ratchet.

5. A retractor as claimed in claim 3 or 4, wherein said means operable to connect said member to said reel comprises cam means

provided on said frame for engagement by said pawl to release said pawl from said ratchet when said reel rewinds a predetermined amount under the bias of said second spring means and stop means provided on said member to limit pivoting movement of said pawl away from the ratchet under the action of said cam.

6. A retractor as claimed in claim 3, wherein said means operable to connect said member to said reel comprises cam means arranged to be frictionally driven by rotation of said reel to activate said pawl and ratchet means upon a slight rewind movement of said reel following an unwinding movement thereof and cam means mounted to said frame to be engaged by said pawl and ratchet means to deactivate the pawl and ratchet means upon rotation of said member and reel in a rewind direction under the bias of said second spring means by a predetermined amount.

7. A retractor as claimed in claim 1, 2 or 3, including spiral cam surface means mounted to said frame and presenting a spiral surface having an extent of more than one full revolution about a spiral centre, cam follower means arranged to be driven along said surface in direct response to rotation of said reel, and means actuable in response to radial displacement of said follower relative said spiral centre due to travel of more than one full revolution about said centre for operating said means for connecting said member to said reel to release said member from said reel.

8. A retractor as claimed in claim 7, wherein when appended to claim 3, the pawl is mounted for rotation concurrent with rotation of said member, and said means operable in response to radial displacement of said follower includes abutment means for engaging said pawl during rotation thereof and moving said pawl into a release position.

9. A retractor as claimed in claim 7 or 8, wherein said retractor includes a cover and said spiral surface is formed on an inside surface of said cover.

10. A retractor as claimed in any preceding claim, wherein said first spring means comprises a first coil spring having a central axis coaxial with said member and said reel, and said second spring means comprises a second coil spring having a central axis parallel to and spaced from the axis of said first spring means.

11. A retractor as claimed in claim 10, wherein said second spring means comprises a portion disposed laterally of said first spring means and a further portion wound about said member.

12. A retractor as claimed in claim 10, wherein said member is provided with peripheral gear teeth, and said second spring means includes a surrounding outer gear member having teeth meshing with the teeth of said member.

13. A safety belt retractor substantially as herein described with reference to Figures 1 to 8, Figures 9 to 14 or Figures 15 to 23 of the accompanying drawings.

14. A safety belt retractor comprising a safety belt storage reel, and first spring means for biasing said reel in a belt rewind direction, second spring means actuable to provide a reduced rewind bias on said reel, means for activating said second spring means in response to reel rotation in a predetermined manner, and means for deactivating said second spring means in response to reel rotation, in a belt rewind direction, or more than one full revolution while the second spring means is activated, the deactivating means including a spiral cam surface and a cam follower arranged to be driven along the cam surface by rotation of said reel when the second means is activated.

15. A retractor as claimed in claim 14, wherein means are provided for mounting said follower for concurrent rotation at substantially the same angular speed as said reel, and said spiral cam surface has an extent of greater than one revolution, whereby said reel may rotate more than one revolution while the second spring means is activated before said second spring means is deactivated.