GB1583538A

GB1583538A - Towing brackets for connecting vehicles with trailers

Info

Publication number: GB1583538A
Application number: GB19016/78A
Authority: GB
Original assignee: BRINK BV
Current assignee: BRINK BV
Priority date: 1977-05-11
Filing date: 1978-05-11
Publication date: 1981-01-28
Also published as: SE422179B; FR2390304A1; DK145533B; NL168452C; LU79625A1; CH638140A5; FR2390304B1; NL7705201A; DK145533C; AT376618B; FI63187C; DE2819763A1; FI63187B; BE866599A; DE2819763C2; NO150427B; NL168452B; NO150427C; DK205278A; IT7823204A0

Abstract

A securing device (2) for a removable drawbar (1) to which a trailer can be coupled is provided on the towing vehicle. The drawbar (1) is to be capable of being removed and mounted as easily as possible and yet is to form a secure coupling between towing vehicle and trailer. For this purpose, the drawbar (1) is guided laterally by the securing device (2) and is held, for the purpose of providing vertical support, on three securing elements (19, 23, 29) which are mutually spaced in the longitudinal direction of the drawbar (1). A fixed support point (19) below the drawbar (1), a fixed support point (8, 23) above the drawbar (1), which support point (8, 23) fixes the drawbar in the longitudinal direction, and a movable support point (29) which presses against a rounded-off profile (11) on the underside of the drawbar (1) under spring effect and interacts with the said drawbar (1) in a self-locking way serve as securing elements. <IMAGE>

Description

(54) IMPROVEMENTS IN OR RELATING TO TOWING BRACKETS FOR CONNECTING VEHICLES WITH TRAILERS (71) We, BRINK B.V., of Industrieweg 5, Staphorst, the Netherlands, a Dutch Company, 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 towing brackets for connecting vehicles with trailers. Such a bracket may comprise a ball rod carrying a coupling ball and a retaining device for the ball rod for attachment to a car body which retaining device is provided with a locking member with a securing device.

In a known embodiment of a towing bracket, a round ball arm is enclosed between straightly rearwardly extending ears spaced from each other and mounted on a pipe attached to the car body, filling rings (spacers or washers) being located between the arm and the ears at both sides and bolts being inserted through the ears, the filling rings and the ball arm which can be drawn tight by way of nuts. The free end of the ball arm may be bent upwards and grip around the pipe. A drawback of this known construction is that the mounting and dismounting of the ball arm is a complicated and time-consuming job while the loose mounting accessories, namely the bolts, nuts and filling rings can easily be lost. Also, tools are necessary for assembling and disassembling the ball arm.

Another towing bracket is known in which the truncated conical end of the ball rod engages a shank with a truncated conical cavity, the front extremity of the ball rod and that of the shank being provided with a transverse bore through which a pin with an eccentric part can be inserted, it being possible to draw the ball rod tight in the shank when the pin is rotated around its axis. This known embodiment has the drawback that it is sensitive to dirt and attack of the cooperating conical surfaces of the rod and the shank.

None of the known constructions for towing brackets complies with all design specifications of the Dutch Government Office for Road Traffic. As to closing or locking, these design specifications read: General: 1. The locking member should operate under resilient pressure.

2. The securing device should be satisfactory.

3. It should not be possible to open the locking member during normal service when the securing device is not in operation.

4. Manual or automatic readjustment should be possible in case wear occurs.

5. Pivoting pins in the locking member should be stationarily connected with the housing.

Securing device: When removing the spring of the locking member the securing device should be sufficiently strong, the securing device should not be loaded during normal use, the securing device should be visible from the outside and it should be possible to activate the securing device in locked position only.

The above described first-mentioned known towing bracket does not comply with the specifications sub-point 1, point 3 and point 4. The second known towing bracket does not comply with the specifications sub-point 1 and point 5. Furthermore the above-described known towing brackets at least do not comply with the first-mentioned requirement as to the necessary strength.

According to the invention, there is provided a towing bracket for connecting a vehicle with a trailer, comprising a ball rod carrying a coupling ball, and a retaining device for attachment of the ball rod to the body of the vehicle, the retaining device being provided with a locking member for locking the ball rod to the retaining device and having a securing device for securing the locking member in its locking position, the ball rod being supported in the retaining device in a vertical sense in three regions spaced from each other in the longi tudinal direction of the rod and laterally enclosed in the retaining device, the three support regions, which comprise two fixed support regions and one movable support region, forming the apices of a triangle, the retaining device engaging the upper side of the ball rod at the central stationary support region and securing the rod in the longitudinal direction, the movable support region which is farthest from the coupling ball being defined by engagement of the under side of the ball rod and the locking member and being displaceable by movement of the locking member against spring action, the locking member being displaceable to a position out of engagement with the ball rod and cooperating with a round profile of the ball rod so as to tend to remain in engagement with the round profile.

A preferred towing bracket can be mounted and dismounted particularly readily without tools and it is not necessary to use loose mounting accessories which can easily be lost. Owing to the position of the support regions for the ball rod at the apices of a triangle and the movable but self-engaging arrangement of the displaceable support region, an optimum safety during use may be achieved with the preferred towing bracket. The towing bracket complies with all design specifications of the Government Office for Road Traffic. Furthermore, the towing bracket is insensitive to dirt and it cannot be mounted in a wrong way.

When a downward force is exerted on the ball, which is the case during normal use, the towing bracket is supported in the vertical direction at the two stationary support regions and retained in the longitudinal direction by the central support region, whereas, when an upward force is exerted on the ball, the rod is supported in vertical direction at the central support region and the movable support region which remains in its place owing to the spring action on the locking member and its self-engaging action.

Preferably, the ball rod has a rectangular cross-section and is mounted between upstanding sidewalls of the retaining device, the support region nearest the coupling comprising the region of contact between a plate fixedly connected with the side walls of the retaining device and the lower face of the ball rod, the central support region comprising the regions of contact between a round pin mounted in the side walls of the retaining device and a V-shaped recess in the upper face of the ball rod, and the part of the locking member defining the support region furthest from the coupling ball comprising a horizontal locking pin disposed between cheeks of the locking member, the side cheeks at the upper side being pivotally mounted on projecting portions of a horizontal pin fixedly mounted in and extending from both side walls of the retaining device, one of the cheeks being provided with a handle and one of the cheeks being connected with one of the sidewalls by means of a pull spring, the locking pin pressing against the round profile at the lower face of the free end of the ball rod and the distance between the vertical centre lines through the round pin of the central support region and through the horizontal pin of the locking member being greater than the distance between the vertical centre lines through the round pin at the central support region and through the centre of curvature of the round profile, the securing device being provided with a hookshaped member biased by spring action, which member cooperates automatically with a fixed part of the retaining device.

Hereby a particularly reliable and simple construction of the preferred towing bracket is achieved with which the design specifications of the Government Office for Road Traffic are complied with in a simple way.

Preferably, in the assembled position, a triangle is formed by the centre point of the horizontal pin, the contact region between the locking pin and the round profile of the ball rod, and the centre of curvature of the round profile, of which triangle the angle enclosed by the triangle sides at the contact region is greater than 0 -and smaller than 10 , the shortest distance between the centre of curvature and the lower face of the ball rod being equal to the radius of curvature of the round profile.

The angle enclosed by perpendiculars dropped on these triangle sides towards the centre of the horizontal pin and the centre of curvature respectively is also greater than 0 smaller than 10 due to which the locking pin tends to maintain engagement with the curvature of the round profile at the under side of the ball rod.

The invention will be further described by way of example with reference to the accompanying drawings, in which; Figure 1 is a side view of a preferred towing bracket with retaining device; Figure 2 is a top view of the towing bracket with retaining device of Figure 1; Figure 3 is a top view of the locking member with securing device of the preferred towing bracket; Figure 4 is a side view of a ball rod holder; Figure 5 is a side view of the free end of the ball rod; and Figure 6 shows the mutual arrangement of a pivot pin of the locking member, a locking pin, the centre of curvature of the round profile at the underside of the ball rod and the contact point of the round profile at the locking pin.

The preferred towing bracket, as shown in Figures 1, 2 and 3, comprises a ball rod 1, a retaining device 2, a locking member 3, and a securing device 4.

The ball rod 1, as shown in Figure 1, comprises a rectangular rod 5 with rounded corners which, by means of an upwardly curved and tapering portion 6 merges into a coupling ball 7 proper which can be coupled to the pole shaft of a trailer (not shown). Near its other extremity 9, the rod 5 is provided in its upper face with a V-shaped recess 8, the boundary faces of which enclose an angle of 90" and are symmetrical in respect of the vertical centre line of the recess 8. At the free extremity 9, the rod 5 is provided in its upper face with an obtuse angled recess 10 and at its lower face with a round profile 11 which will be further described hereinbelow.

The retaining device 2 (Figures 1 and 2) comprises an integral angle piece 12 and a ball rod holder 13 proper which comprises two vertical plates 14 and 15. The plates 14 and 15, at their upper edges and front edges, are welded to a horizontal flange 16 and a vertical flange 17, respectively, of the angle piece 12. The flanges 16 and 17 of the angle piece are provided with mounting holes 18 for attachment to a vehicle, e.g.

by means of an auxiliary construction (not shown).

Between the plates 14 and 15, at their rear ends facing the coupling ball 7, a sup port plate 19 (Figures 1 and 4) is provided and comprises a horizontal flattened por tion 20 and an obliquely downwardly ad jacent portion 21 integral with the portion 20. The function of this support plate 19 will be further described hereinbelow.

According to Figure 1, the plates 14 and 15 of the ball rod holder 13 are provided in their upper edges with a U-shaped recess 22, a pin 23 resting against the horizontal flange 16 of the angle piece 12 in the recesses 22, which pin is attached to the plates 14 and 15 and/or to the horizontal flange 16. Furthermore, a bore 24 is made in the plates 14 and 15 adjacent the front ends of the plates and a recess 25 is formed in the foremost lower angle, all this being further described hereinbelow.

In the bore 24 in the plates 14 and 15 a pin 26 is non-rotatably secured (Figure 1) on which pin cheeks 27 or 28 are mounted at the ends thereof at both sides projecting from the plates 14 and 15, which cheeks are connected with each other at their lower end by a pin 29. The cheek 27 of the locking member 3, formed by the cheeks 27 and 28 and the pin 29, is pro vided with a bore 30 and at the rear end of the plate 14 of the ball rod holder 13 a pin 31 is fastened, a pull spring 33 being tensioned between the bore 30 and the pin 31.

Approximately at right angles with respect to the cheek 28 of the locking member 3, a handle 34 is formed being integral with the cheek 28. A three-armed lever 36 of the securing device 4 is pivotally mounted on the handle 34, a second arm 36" of which lever is provided at its extremity with a hook 37 and a first arm 36' with a handle 38 fastened at right angles to the arm. A third arm 36"' is connected with the handle 34 by means of a pull spring 39 which pull spring 39 is hooked by means of its eyes to a pin or eye 40 of the third arm 36"' and in a notch 41, respectively, in the handle 34.

The spring 39 pulls the second arm 36" in clockwise direction with the front against a pivot 42 of the support pin 23, which pivot protrudes beyond the plate 15 of the ball rod holder 13. At the upper side of the hook 37, the second arm 36" is provided with a cavity 37' the bottom of which, at least partially, has a radius of curvature corresponding with the radius of the round pivot 42 of the support pin 23. The significance hereof will be further described hereinbelow. Furthermore, the third arm 36"' is provided at its upper end with an inwardly extending pin 36a fastened at right angles to the arm, which pin is situated within the path of movement of the ball rod 1 in the holder 13 when assembling the ball rod and the meaning hereof will be further described hereinbelow.

In assembled condition, the ball rod 1 bears with its lower face on the flattened portion of the support plate 19, engages the support pin 23 of the retaining device 2 in the V-shaped recess 8 in the upper face of the ball rod 1, and presses the locking pin 29 against the round profile 11 at the front lower side of the ball rod 1 by means of the tension of the spring 33.

The disassembling and assembling of the ball rod 1 proceed as follows (vide Figures 1, 2 and 3); when disassembling the ball rod 1, first the three-armed lever 36 is withdrawn against the tension of the spring 39 with the thumb on the handle 38, the hook 37 on the arm 36" being released from the pivot 42, and then the locking lever 34 is manually turned anticlockwise, the pin 29 of the locking member 3 being released from the round profile 11 at the lower side of the front end of the ball rod 1, which then, turning in a clockwise direction around the support 19 in the retaining device 2, can be lifted, is released from the pin 23 and can be drawn from the retaining device over the obliquely downwardly directed portion 21 of the plate 19.

When disassembling the ball rod 1, the locking member can be turned in a anticlockwise direction so far that the cavity 37' at the upper side of the hook 37 can engage below the pivot 42 so that the locking member 3 and the securing device 4 can remain in this open position of the retaining device 2.

When assembling the ball rod 1 by manual force it is introduced in such a way by pressing and simultaneously generating a small anticlockwise torque, that the ball rod 1 at its lower side is guided over the oblique plate 21 and, at the upper side along the support pin 23. After having been introduced over a sufficient distance, the Vshaped recess drops around the support pin 23, the ball rod 1 tilting anticlockwise and the free end 9 moving upwards. During the anticlockwise tilting of the ball rod 1 in the holder 2, the ball rod presses with its upper face against the pin 36a of the securing lever 36 due to which the latter pivots in anticlockwise direction and the cavity 37' is released from the pivot 42.

The locking member 3 can now turn in a clockwise direction. Under the influence of the spring 33, the locking pin 29, due hereto, drops under the round profile 11 of the ball rod 1, owing to which locking is effected automatically. Because of the pulling of the locking member 3 by the spring 33 also the handle 34 moves upwardly, the hook 37 of the securing arm 36", under the influence of the spring 39, engaging behind the protruding pivot 42 of the support pin 23 and the locking being moreover automatically secured.

The operation of locking of the preferred towing bracket is as follows: When the vehicle draws a trailer by means of the towing bracket, a rearwardly directed tensile force is exerted on the ball 7 and an anticlockwise directed torque on the ball rod 1 which torque presses the ball rod on the portion 20 of the plate 19 and the V-shaped recess 8 on the pin 23. The spring 33 retains the locking member 3 in its place and presses the pin 29 against the round profile.

When the vehicle does not draw the trailer, e.g. when driving down a slope, a clockwisely directed torque is exerted on the ball rod 1, the V-shaped recess 8 pressing on the pin 23 and the round profile 11 exerting a force on the pin 29 of the locking member 3. However, the locking member 3 keeps locking the ball rod 1, because the spring 33 keeps pulling the locking member 3 and a self-locking action takes place between the locking pin 29 and the round profile 11. When the spring 33 breaks or gets loose, the locking pin 29, even during the exertion of a clockwise torque by the trailer on the ball rod 1, keeps pressing against the round profile 11 at its initial position, due to the self-locking action between the locking pin 29 and the round profile and the locking member 3 does not make any rotating movement in an anticlockwise direction.At all times a manual pressure has to be exerted on the lever 34 to release the locking pin 29 from the round profile 11.

When in the case of a broken spring 33 of the locking member 3, the locking member would make a pivoting movement in an anticlockwise direction due to unexpected conditions, this movement of the locking member 3 is stopped because the hook 37 of the second arm 36" of the securing lever 36 engages behind the protruding pivot 42 of the support pin 23 before the locking pin 29 gets out of engagement with the round profile 11.

The self-locking action between the round profile 11 and the locking pin 29 is accomplished in the following way (vide Figures 1,4,5and6).

The distance a between vertical centre lines A and B through the round pin 23 of the second support pin and the pivot pin 26 of the locking member 3 is larger than the distance b between vertical centre lines A and C through the support pin 23 and through the centre of curvature D of the round profile 11, a triangle being formed in assembled condition by the centre G of the pivot pin 26, the contact point F of the locking pin 29 with the round profile 11 of the ball rod 1 and the centre of curvature D, the angle ex enclosed by the connecting lines from F to G and D, respectively, being larger than 0 and smaller than 10 which then also applies to the angle 0 enclosed by the lines through the contact point F and perpendicular to these connecting lines from F to G and D, respectively (vide Figure 6) and the shortest distance c between the centre of curvature D and the lower face of the ball rod 1 being equal to the radius of curvature d of the round profile 11.

The following dimensions have been applied to an actual preferred towing bracket (vide Figures 4 and 5).

The distance a between the vertical centre lines A and B through the round support pin 23 (or recess 22) of the second support point and through the pivot pin 26 (or the bore 24) amounts to 34 mm and the distance b between the vertical centre lines A and C through the support point 23 and the centre of curvature D of the round profile 11 amounts to 31-5 mm. The shortest distance c between the centre of curvature D and the lower face of the ball rod 1 which is equal to the length of the radius of curvature d amounts to 29 mm.

With the preferred towing bracket, all manufacturing tolerances and those caused by use (wear), if any, can be taken up by displacement of the contact point F be tween the locking pin 29 and the round profile 11 which position is determined exclusively and alone by the tolerances formed.

WHAT WE CLAIM IS: - 1. A towing bracket for connecting a vehicle with a trailer, comprising a ball rod carrying a coupling ball, and a retaining device for attachment of the ball rod to the body of the vehicle, the retaining device being provided with a locking member for locking the ball rod to the retaining device and having a securing device for securing the locking member in its locking position, the ball rod being supported in the retaining device in a vertical sense in three regions spaced from each other in the longitudinal direction of the rod and laterally enclosed in the retaining device, the three support regions, which comprise two fixed support regions and one movable support region, forming the apices of a triangle, the retaining device engaging the upper side of the ball rod at the central stationary support region and securing the rod in the longitudinal direction, the movable support region which is farthest from the coupling ball being defined by engagement of the underside of the ball rod and the locking member and being displaceable by movement of the locking member against spring action, the locking member being displaceable to a position out of engagement, with the ball rod and cooperating with a round profile of the ball rod so as to tend to remain in engagement with the round profile.

2. A towing bracket as claimed in Claim 1, in which the ball rod has a rectangular cross-section and is mounted between upstanding sidewalls of the retaining device, the support region nearest the coupling ball comprising the region of contact between a plate fixedly connected with the side walls of the retaining device and the lower face of the ball rod, the central support region comprising the regions of contact between a round pin mounted in the sidewalls of the retaining device and a V-shaped recess in the upper face of the ball rod, and the part of the locking member defining the support region furthest from the coupling ball comprising a horizontal locking pin disposed between cheeks of the locking member, the cheeks at the upper side being pivotally mounted on projecting portions of a horizontal pin fixedly mounted in and extending from both side-walls of the retaining device, one of the cheeks being provided with a handle and one of the cheeks being connected with one of the sidewalls by means of a pull spring, the locking pin pressing against the round profile at the lower face of the free end of the ball rod and the distance between the vertical centre lines through the round pin at the central support region and through the horizontal pin of the locking member being greater than the distance between the vertical centre lines through the round pin at the central support region and through the centre of curvature of the round profile, the securing device being provided with a hook-shaped member biased by spring action, which member cooperates automatically with a stationary part of the retaining device.

3. A towing bracket as claimed in Claim 2, in which, in the assembled condition, a triangle is formed by the centre of the horizontal pin, the contact region between the locking pin and the round profile of the ball rod, and the centre of curvature of the round profile, of which triangle the angle enclosed by the triangle sides at the contact region is greater than 0 and smaller than 100, the shortest distance between the centre of curvature and the lower face of the ball rod being equal to the radius of curvature of the round profile.

4. A towing bracket as claimed in Claim 2 or 3, in which the securing device comprises a three-armed lever pivotally mounted on a handle of the locking device, which lever by means of a pull spring is connected with the handle and, with its central arm, rests against a pivot of the round pin, the central arm above the pivot being provided with a hook.

5. A towing bracket as claimed in Claim 4, in which the central arm of the threearmed lever is provided above the hook with a cavity arranged to cooperate with the pivot of the round pin so that both the locking member and the three-armed lever can be held in the open inoperative position, the three-armed lever at the side facing the pull spring being provided with a third arm which is provided at its free end with a pin located at right angles to the arm, which pin in the open position of the locking member and the three-armed lever lies in the path of movement of the ball rod during the assembling thereof.

6. A towing bracket as claimed in any one of Claims 2 to 5; in which the retaining device is covered at the upper side and the side facing away from the ball rod by an integral angle piece for attachment to the body of the vehicle, the plate fixedly connected to the side walls of the retaining device comprising a horizontal flattened portion and an obliquely downwardly inclined adjacent and integral portion, the ball rod having a substantially square cross

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. tween the locking pin 29 and the round profile 11 which position is determined exclusively and alone by the tolerances formed. WHAT WE CLAIM IS: -

1. A towing bracket for connecting a vehicle with a trailer, comprising a ball rod carrying a coupling ball, and a retaining device for attachment of the ball rod to the body of the vehicle, the retaining device being provided with a locking member for locking the ball rod to the retaining device and having a securing device for securing the locking member in its locking position, the ball rod being supported in the retaining device in a vertical sense in three regions spaced from each other in the longitudinal direction of the rod and laterally enclosed in the retaining device, the three support regions, which comprise two fixed support regions and one movable support region, forming the apices of a triangle, the retaining device engaging the upper side of the ball rod at the central stationary support region and securing the rod in the longitudinal direction, the movable support region which is farthest from the coupling ball being defined by engagement of the underside of the ball rod and the locking member and being displaceable by movement of the locking member against spring action, the locking member being displaceable to a position out of engagement, with the ball rod and cooperating with a round profile of the ball rod so as to tend to remain in engagement with the round profile.

section and being provided at its free end at the upper side with an obtuse angle recess.

7. A towing bracket for connecting a vehicle with a trailer, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.