GB1572306A

GB1572306A - Safety belt clamp apparatus and restraint system

Info

Publication number: GB1572306A
Application number: GB49719/77A
Authority: GB
Original assignee: Allied Chemical and Dye Corp; Allied Chemical Corp
Current assignee: Allied Corp
Priority date: 1976-11-30
Filing date: 1977-11-29
Publication date: 1980-07-30
Also published as: FR2371939A1; IT1091511B; DE2752860A1; JPS5371418A; CA1103218A; FR2371939B1; ES464562A1; SE436834B; DE2752860C2; SE7713493L

Description

(54) IMPROVED SAFETY BELT CLAMP APPARATUS AND RESTRAINT SYSTEM (71) We, ALLIED CHEMICAL CORPO RATION, a Corporation organized and existing under the laws of the State of New York, United States of America, of Columbia Rd, and Park Avenue, Morris Township, Morris County, New Jersey 07960, 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 statement : The present invention relates to an improved belt clamp appartus and to an improved vehicle occupant restraint system having a safety belt which is movable through the clamp apparatus.

The belt clamp apparatus is an improvement of a belt clamp apparatus described in the specification of United States Patent No. 3,847,434.

According to the present invention there is provided a belt clamp apparatus for use with a safety belt where the safety belt is movable through the clamp apparatus in a first direction and in an opposite second direction, said clamp apparatus being adapted to resist movement of said belt in said first direction when a force above a first predetermined amount is applied to said belt in said first direction, said clamp apparatus including a lever pivotable on a first shaft between a clamping position and a non-clamping position; a first biasing means biasing said lever member to its nonclamping position; a clamp bar having a first surface for contacting a portion of the belt; a mounting means for the lever for movably mounting the bar on the lever, said mounting means comprising a channel in the lever; means for retaining the bar in said mounting means of said lever, said retaining means comprising lip means associated with said channel, said clamp bar being freely movable within said channel; and pivot means on a second surface of said clamp bar opposite from said first surface, said clamp bar being movable on said pivot means with respect to said lever for applying a force distributed over an area of contact on said belt. Preferably the pivot means comprises a crest surface.

The clamp apparatus may further include a pivot means for moving a portion of the apparatus in a substantially vertical plane and a swivel means for moving a portion of the apparatus in a substantially horizontal plane. The clamp apparatus may further include resilient bushing means within the lever for evenly distributing force applied by the lever laterally across the width of the belt.

The invention will be further described, by way of example, with reference to the accompanying drawings, wherein: Figure 1 is a vertical section view of a belt clamp embodying the invention; Figure 2 is a perspective exploded view of a bracket for supporting the clamp of Figure 1, Figure 3 is vertical sectional view, to a smaller scale, of the clamp of Figure 1 mounted on the bracket of Figure 2; Figure 4 is a horizontal section taken along the line 4-4 in Figure 3; Figure 5 is a side view of the belt clamp shown in Figure 3; Figure 6 is a partial horizontal section taken along the line 6-6 in Figure 5; Figure 7 is a horizontal section taken along the line 7-7 in Figure 1; and Figures 8, 9 and 10 are perspective views of an improved occupant restraint system in a vehicle using the improved belt clamp apparatus of Figures 1 to 7.

Referring to Figure 1, belt clamp apparatus 2 may be used with a vehicle occupant restraint system having a shoulder belt 4. For example, the belt clamp apparatus 2 may be used as a substitute for a bracket in a restraint system as described in U.S. Patent 3,847,434. The belt 4 is movable throughout the belt clamp apparatus 2 in a first unwinding direction 6 in which the belt 4 becomes more loose around the occupant and in an opposite second winding direction 8 in which the belt 4 becomes tighter around the occupant. The belt clamp apparatus 2 includes a lever 10 pivotable on a first shaft 36. The belt clamp apparatus 2 resists movement of the belt 4 in the first unwinding direction 6 when a force above a predetermined amount is applied to the belt 4 in the unwinding direction 6. The lever 10 has a clamping position shown in Figure 5 and a nonclamping position, shown in Figures 1 and 3.

The clamp apparatus includes a clamp means comprising a clamp bar 12, a mounting means 14 for the clamp bar 12 adjacent to a lower end of the lever 10, a longitudinal crest 16 along the longitudinal axis of the clamp bar 12 and a first biasing means 13 for biasing the lever to its non clamping position. The clamp bar 12 has a first surface 18 for contacting a portion of the belt 4. The mounting means 14 is illustrated as a channel 20 in the lever 10 in which the clamp bar 12 is disposed. The lever 10 also includes retaining means for retaining the bar 12 in the channel 20. The crest 16 is disposed on a second surface of the bar 12 opposite from the first surface 18 which is contactable with a portion of the belt 4. The bar 12 is movable on the crest 16 in the channel 20 for applying a substantially uniform force over an area of contact of the belt 4.

The retaining means for retaining the bar 12 in the channel 20 includes a first lip 22 on a first side of the channel 20 and a second lip 24 on a second opposing side of the channel 20. A recess 26 is provided in the bar 12 adjacent to the first lip 22 and a second biasing means, which may be a spring 28, is disposed in the recess 26 between the bar 12 and the first lip 22 of the lever 10. The spring 28 biases the bar 12 away from the portion of the belt 4 adjacent to the first surface 18, and prevents the surface 18 from interfering with free movement of the belt 4 when the lever is in its non-clamping position shown in Figures 1 and 3. The spring 28 also prevents rattle of the bar 12 within the recess 20.

Referring to Figures 1 and 2, the mounting bracket comprises a pivot means 30, for supporting the lever 10 and its associated components for movement in a substantially vertical plane and a swivel means 32 for supporting the lever 10 and its associated components for movement in a substantially horizontal plane. The pivot means 30 includes a base member 34 having a first side 38 and a second side 40 disposed parallel to one another in substantially vertical planes. The first and second sides 38 and 40 project forwardly as the legs of a U shape, the bight of which is formed by the base member 34. The lever 10 is disposed between the first and second sides 38 and 40 and a first shaft 36 extends substantially horizontally through the first and second sides 38 and 40 and through the lever 10 pivotally to support the lever 10 and its associated components. The base member 34 is provided with a third side 42 and a fourth side 44 disposed parallel to one another and extending substantially horizontally from the base member as legs extending rearwardly from the base member 34. The swivel means 32 includes a Ushaped bracket member 46 and second shaft 48. The bracket member 46 comprises forwardly projecting parallel substantially horizontal sides 51 and 52. The second shaft 48 extends substantially vertically through the third and fourth sides 42 and 44 and the sides 50 and 52 of the bracket member 46. As a result, the base member 34, the lever 10 and its associated components swivel on the second shaft 48 through a substantially horizontal plane with respect to the bracket member 46.

Referring to Figures 1 and 3 to 6, the biasing means 13 is a wire spring 54. Referring to Figure 4, the spring 54 has an elongated portion 56 and two ends. The spring 54 has a hairpin turn 58 at each of its ends and two legs 60 and 62.

Referring to Figure 7, two resilient bushings 72 are preferably fitted within the lever 10 and around the shaft 36 extending laterally between the first side 38 and the second side 40 of the first bracket 34. The bushings 72 evenly (distribute the force applied by the lever 10 laterally across the width of the belt 4 adjacent to surface 18.

The bar 12 movable on the crest 16 serves to equalize the force applied by the belt 4 longitudinally along the length of the portion of the belt 4 contacted by the bar 12. The bushings 72 also maintain an approximately constant space between the belt 4 and the bracket 34 and between lever 10 and the belt 4. The bushings 72 also compensate for slight errors in placement of the holes 74 and 76 in the first and second sides 38 and 40 through which the first shaft 36 fits.

In operation, when a force above a predetermined amount is applied in a first direction 6 to the belt 4, it moves the lever 10 from its non-clamping position shown in Figures 1 and 3 to its clamping position shown in Figure 5. Such force above a predetermined amounts compresses the legs 60 and 62 of the spring 54 from their posi tion shown in Figure 4 to their position shown in Figure 6. This surface 18 of the bar 12 applies a substantially uniform force over an area of contact on a portion of the belt 4 adjacent to the surface 18. Such area contact rather than a line of contact by an edge of the surface 18, or point contact, improves the clamping action on the belt 4. Area contact is obtained by movement of the bar 12 on the crest 16, in conjunction with action of the bushings 72 and in conjunction with pivoting action in two planes on shafts 36 and 48. As a result, the force applied by surface 18 is substantially perpendicular to the plane of the belt 4 adjacent to surface 18. The surface 18 has frictional means, such as knurls, for applying a braking force to the belt 4 to stop movement of the belt 4 through the clamp apparatus 2 in the first unwinding direction 6.

An abutment surface 66 on the side of the base member 34 facing surface 18 also may have a frictional means, such as knurls, for applying a braking force on the opposite side of the belt 4 to assist in stopping movement of the belt 4 in first unwinding direction 6. In the clamping position of the apparatus 2, shown in Figure 5, the belt 4 is squeezed between the surface 18 and the abutment surface 66.

Braking force on the portion of belt 4 between the surfaces 18 and 66 is applied by the lever 10 through the crest 16. There are several means for varying the amount of braking force applied to the belt 4. One means is to vary the type of frictional surface on surface 18 and on surface 66.

Another means is to vary the leverage applied. The leverage applied is a function of a first distance 68 (Figure 1) from the first shaft 36 to the top of the lever 10 where the belt 4 goes around the lever and a second distance 70 from the first shaft 36 to the crest 16. More specifically, the leverage is a function of the ratio of distance 68 to distance 70. Varying the amount of force applied by the lever 10 to the belt 4 between surfaces 18 and 66 may, if desired allow controlled slippage of the belt 4 through the apparatus 2 in an unwinding direction 6.

Referring to Figures 8 to 10, the belt clamp apparatus 2 may be used in an improved safety restraint system 78 for a seated occupant in a vehicle. The restraint system 78 includes a shoulder belt 80 passing over a shoulder of the seated occupant.

Typically, the system 78 also includes a lap belt 82 passing over the lap of the occupant. The belt clamp apparatus 2 is mounted in the vehicle at or above a horizontal plane in the vehicle passing over a shoulder of a seated occupant in the vehicle, such as on a "B-pillar" or the vehicle or on the roof of the vehicle. The belt clamp apparatus 2 is responsive to an unwinding force on the belt 80 above a first predetermined amount, for example, about forty (40) Newtons, resulting from a pull on the shoulder belt 80 when the seated occupant lurches forward as a result of an emergency condition. The safety restraint system 78 also includes a retractor 84 mounted in the vehicle below the belt clamp apparatus 2 for allowing unwinding of the shoulder belt in the first direction 6 out of the retractor 84 and for winding and shoulder belt in the second direction 8 into the retractor 84.

The belt clamp apparatus 2 may be used in a variety of ways in the improved safety restraint system 78, such as to provide: a belt sensitive safety restraint system, or a vehicle sensitive safety restraint system, or a dual sensitive safety restraint system, or a force limiting safety restraint system. If a belt sensitive safety restraint system is desired, the retractor 84 may be a simple, inexpensive non-locking retractor. A belt sensitive safety restraint system is a system responsive to force applied on the shoulder belt 80 in the first direction 6, causing a portion of the belt means 80 to be unwound from the retractor 84. A non-locking retractor allows the shoulder belt means 80 to be freely wound and unwound from the retractor under all conditions. An example of a non-locking retractor is described in the specification of United States Patent No. 3,445,078. In such a belt sensitive system having a non-locking retractor, the belt clamp apparatus 2 provides the safety restraint system with belt sensitive capability. The belt clamp apparatus 2 in response to an unwinding force on the belt 80 above the first predetermined amount, for example, about forty (40) Newtons, clamps against the belt 4 between surface 18 and surface 66 (Figure 1), stopping further movement of the belt 4 through the belt clamp apparatus 2 in the first direction 6. Such a non-locking retractor may be simple and inexpensive because it need not have a capacity for withstanding force above the first predetermined amount and because it need not have a locking mechanism, a vehicle sensitive inertial mechanism, or belt sensitive mechanism.

If a vehicle sensitive safety restraint system is desired, the belt clamp apparatus 2 may be used in combination with a vehicle sensitive retractor. A vehicle sensitive restraint system is responsive to force applied on the vehicle, such as acceleration, deceleration or change in orientation of the vehicle. The belt clamp apparatus 2 is arranged so that a comparatively high amount of force is required to move the belt clamp apparatus 2 to its clamping position, shown in Figure 5. This may be arranged, for example, by providing a very strong spring 54. As a result, the vehicle sensitive retractor comes into play during an emergency condition before the belt clamp apparatus 2 can be moved to its clamping position. The vehicle sensitive retractor is responsive to acceleration, deceleration or change in orientation of the vehicle and has a locking mechanism within the retractor which locks the reel of the retractor and prevents further unwinding of the safety belt means 80 from the retractor.

Examples of vehicle sensitive retractors are shown in the specification of United States Patents 3,838,831; 3,901,461; 3,913,861, 3,913,862 and 3,940,083.

If a dual sensitive safety restraint system is desired, the belt clamp apparatus 2 may be used in combination with a vehicle sensitive retractor. A dual sensitive safety restraint system is responsive to force applied on the vehicle and is also responsive to force applied on the shoulder belt 80. The belt clamp apparatus 2 has a comparatively weaker spring 54 than in the vehicle sensitive safety restraint system and provides the restraint system with its belt sensitive capability. The vehicle sensitive retractor provides the safety restraint system 78 with vehicle sensitive capability. Thus, when the occupant lurches forward under emergency conditions and causes a force on the shoulder belt 80 above the first predetermined amount, for example, about forty (40) Newtons, the belt clamp apparatus 2 clamps against the belt 4 and (Figure 1) prevents further movement of the belt (4 (Figure 1) through the belt clamp apparatus 2.

If a force limiting safety restraint system is desired, the safety belt apparatus 2 may be used in conjunction with a belt sensitive retractor. A force limiting safety restraint system is responsive to a force applied on the belt 80 above a second predetermined amount, for example, about 6000 Newtons, and has a capability for absorbing force above such second predetermined amount, thereby reducing such force above the second predetermined amount, to be applied to the occupant. A belt sensitive retractor is a retractor which has a mechanism responsive to acceleration applied on the safety belt 80. An example of a belt sensitive retractor is described in the specification of United States Patent No. 3,741,496. When a force above the first predetermined amount, for example, about 6000 Newtons, is exerted on the shoulder belt 80, resulting from a pull on the belt 80, when the occupant lurches forward, the belt clamp apparatus 2 clamps against the belt 80 and prevents further movement of the belt 80 through the clamp apparatus until the unwinding force on the belt means 80 reaches a second predetermined amount, for example, about 6000 Newtons, which is greater than the first predetermined value. The belt clamp apparatus 2 provides controlled slippage responsive to unwinding force on the belt 80 above the second predetermined amount resulting from a pull on the belt means 80 when the occupant lurches forward in response to a force above the second predetermined amount, thereby absorbing some or all of the force above the second predetermined amount. If the force on the belt 80 reaches a third predetermined amount, for example, about 7500 Newtons, which is in excess of the second predetermined amount, the belt sensitive mechanism in the retractor comes into play. The belt sensitive mechanism in the retractor locks in responsive to a force above the third predetermined amount, thereby preventing further unwinding of the belt 80 from the retractor. The third predetermined amount is greater than the second predetermined amount which is greater than the first predetermined amount.

The retractor may be dual sensitive, that is, it may also have a vehicle sensitive mechanism which is responsive to acceleration, deceleration or change in orientation of the vehicle and locks a reel in the retractor to prevent further unwinding of the belt.

Examples of dual sensitive retractors are described in the specification of United States Patent Nos. 3,858,824 and 3,918,658.

Controlled slippage of the web through the belt clamp apparatus may be achieved by a variety of means. It may be done by changes in design within the belt clamp apparatus, such as the arrangement of the ratio of the first distance 68 to the second distance 70 which varies the leverage of the lever 10 or by varying the frictional braking force applied by clamping surface 18 or surface 66 or both. It may be achieved by changes in an included angle 86 of the belt. The included angle 86 is the angle formed between the shoulder belt 80 at the top of the clamp apparatus 2 and the shoulder belt 80 at the bottom of the belt clamp apparatus 2. Preferably, the shoulder belt 80 at the bottom of the clamp apparatus 2 lies in a substantially vertical plane. If the clamp apparatus 2 is positioned high on the "B-pillar" near the roof as shown in Figures 8 and 9, the included angle 86 is smaller than if the clamp apparatus 2 is positioned lower on the "B-pillar" closer to the shoulder of the seated occupant as shown in Figure 10. As the included angle 86 becomes greater, approaching the range of 90 -135 , the belt means 80 has more of a tendency to slip through the clamp apparatus 2. Preferably, the included angle 86 is at or less than about 900. Controlled slippage may also be achieved by changes in the surface frictional characteristics of the belt composition or by a combination of the foregoing means. The force limiting restraint system is reusable because the energy absorbing function is not accomplished by a breakable member or any other type of one-time operation.

The shoulder belt 80 may further include an inflatable portion 88 and means for inflating it, such as described in the specification of United States Patents No.

3,841,654; 3,866,940; 3,897,081; 3,888,503; 3,877,719; 3,970,329; 3,929,348 and 3,820,842.

The retractor 84 may be positioned on the floor of the vehicle, as shown in Figures 8 and 10, or on a " B-pillar " of the vehicle, as shown in Figure 9. The restraint system 78 may include a buckle 90 and a tongue 92 for the buckle 90. The tongue 92 may be arranged so that the belt means 80 and 82 slide through a portion of the tongue 92.

The belt clamp apparatus 2 prevents unwinding of the belt 80 and 82 resulting from "spool down" and resulting from elongation or stretching of the belt. This is particularly important in restraint systems using a comparatively long length of belt means. "Spool down" occurs when a portion of the belt 80 already wound around a spool or reel inside the retractor 84 is further tightened around the spool by a force in the first direction 6. Even if rotation of the spool is stopped, tightening of belt convolutions around the spool allows a length of belt to be pulled out of the retractor 84. Such "spool down" or elongation would otherwise reduce the ability of the belt means 80 and 82 to restrain an occupant. When the belt clamp apparatus 2 clamps the belt 4, it prevents force in the belt means 80 or 82 from reaching the retractor 84, thereby preventing "spool down" and elongation between the belt clamp apparatus 2 and the retractor 84.

Thus, the belt clamp apparatus 2, and the restraint system in which it is used, reduce forward displacement of the occupant during emergency conditions, such as a vehicle crash, and reduce injuries to the occupant.

WHAT WE CLAIM IS:- 1. A belt clamp apparatus for use with a safety belt where the safety belt is movable through the clamp apparatus in a first direction and in an opposite second direction, said clamp apparatus being adapted to resist movement of said belt in said first direction when a force above a first predetermined amount is applied to said belt in said first direction, said clamp apparatus including a lever pivotable on a first shaft between a clamping position and a non-clamping position; a first biasing means biasing said lever member to its nonclamping position; a clamp bar having a first surface for contacting a portion of the belt; a mounting means on the lever for movably mounting the bar on the lever, said mounting means comprising a channel in the lever; means for retaining the bar in said mounting means of said lever, said retaining means comprising lip means associated with said channel, said clamp bar being freely movable within said channel; and pivot means on a second surface of said clamp bar opposite from said first surface, said clamp bar being movable on said pivot means with respect to said lever for applying a force distributed over an area of contact on said belt.

2. Apparatus according to claim 1, wherein said pivot means comprises a crest surface.

3. Apparatus according to claim 2, wherein said lip means comprises a first lip on one side of said channel and a second lip on the opposite side of said channel.

4. Apparatus according to claim 3, including a second biasing means disposed in said channel and biasing said clamp bar away from said belt.

5. Apparatus according to claim 4, wherein a recess is provided in the bar adjacent to the first lip with a second biasing means being disposed in said recess between the bar and said first lip.

6. Apparatus according to claim 2, 3 or 4, and further comprising a pivot means for mounting a portion of the apparatus for pivotal movement about a substantially horizontal axis, said pivot means comprising a first U-shaped bracket having a pair of spaced parallel sides with the lever being disposed between said sides, said first shaft passing through said two sides and the lever.

7. Apparatus according to claim 6, and further comprising a swivel means for mounting a portion of the apparatus for movement about a substantially vertical axis, said first bracket further comprising a third and fourth spaced parallel sides extending at right angles to the plane of the first pair of sides; and said swivel means comprising a second U-shaped bracket having two spaced parallel sides, and a second shaft passing through said third and fourth sides and the two sides of the second bracket, whereby said first bracket will swivel on the second shaft through a substantially horizontal plane with respect to the second bracket.

8. Apparatus according to claim 2, 3, 4, 5, 6 or 7 including a resilient bushing disposed around the first shaft for evenly distributing the force laterally across the width of the belt.

9. Apparatus according to any preceding

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. changes in the surface frictional characteristics of the belt composition or by a combination of the foregoing means. The force limiting restraint system is reusable because the energy absorbing function is not accomplished by a breakable member or any other type of one-time operation. The shoulder belt 80 may further include an inflatable portion 88 and means for inflating it, such as described in the specification of United States Patents No. 3,841,654; 3,866,940; 3,897,081; 3,888,503; 3,877,719; 3,970,329; 3,929,348 and 3,820,842. The retractor 84 may be positioned on the floor of the vehicle, as shown in Figures 8 and 10, or on a " B-pillar " of the vehicle, as shown in Figure 9. The restraint system 78 may include a buckle 90 and a tongue 92 for the buckle 90. The tongue 92 may be arranged so that the belt means 80 and 82 slide through a portion of the tongue 92. The belt clamp apparatus 2 prevents unwinding of the belt 80 and 82 resulting from "spool down" and resulting from elongation or stretching of the belt. This is particularly important in restraint systems using a comparatively long length of belt means. "Spool down" occurs when a portion of the belt 80 already wound around a spool or reel inside the retractor 84 is further tightened around the spool by a force in the first direction 6. Even if rotation of the spool is stopped, tightening of belt convolutions around the spool allows a length of belt to be pulled out of the retractor 84. Such "spool down" or elongation would otherwise reduce the ability of the belt means 80 and 82 to restrain an occupant. When the belt clamp apparatus 2 clamps the belt 4, it prevents force in the belt means 80 or 82 from reaching the retractor 84, thereby preventing "spool down" and elongation between the belt clamp apparatus 2 and the retractor 84. Thus, the belt clamp apparatus 2, and the restraint system in which it is used, reduce forward displacement of the occupant during emergency conditions, such as a vehicle crash, and reduce injuries to the occupant. WHAT WE CLAIM IS:-

1. A belt clamp apparatus for use with a safety belt where the safety belt is movable through the clamp apparatus in a first direction and in an opposite second direction, said clamp apparatus being adapted to resist movement of said belt in said first direction when a force above a first predetermined amount is applied to said belt in said first direction, said clamp apparatus including a lever pivotable on a first shaft between a clamping position and a non-clamping position; a first biasing means biasing said lever member to its nonclamping position; a clamp bar having a first surface for contacting a portion of the belt; a mounting means on the lever for movably mounting the bar on the lever, said mounting means comprising a channel in the lever; means for retaining the bar in said mounting means of said lever, said retaining means comprising lip means associated with said channel, said clamp bar being freely movable within said channel; and pivot means on a second surface of said clamp bar opposite from said first surface, said clamp bar being movable on said pivot means with respect to said lever for applying a force distributed over an area of contact on said belt.

9. Apparatus according to any preceding

claim, which includes controlled slippage means for allowing movement of the belt through the belt clamp apparatus in said first direction out of a retractor in response to an unwinding force on the belt means above a second predetermined amount greater than said first predetermined amount.

10. Apparatus according to claim 9, wherein the retractor comprises belt sensitive means responsive to an unwinding acceleration on the belt means above a third predetermined amount and locking means for preventing further unwinding of the belt means from the retractor when the unwinding force is above said third predetermined amount, said third predetermined amount being greater than both said first and second predetermined amounts.

11. A belt clamp apparatus constructed and arranged substantially as herein described with reference to and as illustrated in Figures 1 to 7 of the accompanying draw ings.

12. A safety restraint system for a vehicle, such system being constructed and arranged substantially as herein described with reference to and as illustrated in the accompanying drawings.