DE29816329U1 - Device for towing motor vehicles - Google Patents

Description

Konrad Holtermann 298 16 329.2

Große Düwelstr. 15 a
30171 Hanover

Description

Tow bar for motor vehicles

Various solution principles for tow bars are known, which are intended to remedy the known disadvantages of tow ropes. In one known solution, a hollow space is provided on one bar part for the opposite bar part, whereby the free end is surrounded by an insertion funnel and a tip is therefore arranged at the free end of the other bar part, so that the two end pieces can be more easily aligned on a common alignment line and guided into one another. In the operating position, the two bar parts are mechanically coupled to one another in both longitudinal directions by means of a locking device. The solution principle described here is rigid, so that the absorption of shocks and load peaks is not guaranteed.

In another known solution, the tow bar is designed in such a way that it can be pushed together so that it can be stored more easily in the car. The connecting forks can be easily rotated and thus make it easier to couple to the car. A plug pin with a lock ensures a secure connection. A screw with a nut and lock is provided for coupling or connecting the connecting forks.

The rigid solution also described here cannot provide any indication of the principle according to the invention.

A tow bar for motor vehicles is also described, which consists of at least one pipe section with tow hooks hinged on both sides, the receiving mouths of which are open to one another and can each be closed with a straight support that is coaxially inserted into the pipe section and is intended to absorb and transmit pressure forces to the tow bar, which is held in the pipe section so that it can be moved axially and cannot be rotated and whose longitudinal displacement can be blocked by a bolt that passes through the rear wall.

With such tow bars, the distance between the support and the hook mouth in the locking system cannot be adjusted, so that due to the different dimensions of the towing eyes on the vehicle, play can arise between the towing eyes and the hook curvature and the support, which can be disruptive during towing. This solution also does not provide for the damping of load peaks.

An obvious solution is described in a tow bar for motor vehicles, which consists of at least two partial bars, one of which is inserted into another partial bar that is at least partially designed as a tube, whereby the partial bars pushed into one another can be moved longitudinally in a telescopic manner relative to one another.

The system is telescopically adjustable in length and has tubular, interlocking, axially movable rods, whereby the two rods at the ends of the tow bar are equipped with hooks for attaching to the vehicle being towed or to the towing vehicle. The working length is fixed or determined using holes or pins that are predefined by the design. There is also no evidence of any dampening of shock or tensile loads.

Systems that work with coil springs are also known. Here, the tow bar essentially consists of two parts, a rod and a tube, which are connected to each other in a telescopic manner. They are coaxial to each other, with the rod as the inner part being slidably mounted in the tubular outer part.

At the end of the inner rod there is an end plate that can be moved with it. This axial displacement is limited both by a movable, transverse split pin in the tube and by a spring in front of the end ring of the tube. This spring is approximately the same diameter as the inner diameter of the tube and is a coil spring. The end plate forms a support for the spring that is supported on the other side by the end ring. The entire arrangement is thus pushed together telescopically, on the one hand by the coil spring, as this presses on both the end plate and the ring. This pushes the rod into the tube, so that the overall length is reduced when no tension is exerted on the system. In the solution described above, only a limited change in the length of the tow bar is possible; in addition, the buffer travel is limited to tensile stresses, so that pressure surges cannot be absorbed here either and thus lead to dangerous driving situations.

The current tow bars are mostly made up of several parts and are collapsible or telescopic; but usually (apart from a few timid exceptions) they are rigid. At present there is no consistent damping system to prevent the problem of lateral displacement when braking and starting after braking or to reduce it to such an extent that it is no longer relevant for road traffic.

With the rigid tow bars currently in use, it is unavoidable that the vehicle will swerve sideways, and when driving off the vehicle will swerve in the opposite direction, which of course poses a traffic hazard.

The invention is therefore based on the object of creating a tow bar that has a flexible damping effect in both working directions, whose spring constant is adapted to the weights or masses to be towed and which avoids lateral swerving or lateral offset when braking and when starting, so that road safety is significantly improved.

It consists of 3 parts, the middle part of which is designed as a damper using a special spring system, thus enabling smooth starting and braking and thus preventing lateral offset, or at least reducing it to a large extent (corresponding to the towing speed). The solution according to the invention can be found in the claims, the drawings and the drawing description.

Tow bar (three-part), consisting of two tailpipes with vehicle fastening hooks and a spring-loaded center pipe. The spring-loaded center pipe consists of the following parts:

Guide tube (1)

Working tube (2) with bore (4)

Some embodiments of the invention are shown in the drawings. They show:

Fig. 1: Overall view of the system Fig. 2: The tailpipe Fig. 3: Tailpipe with tow hook Fig. 4: Pipe cotter pin Fig. 5: System in tension state Fig. 6: System with loose blocker Fig. 7: System in braking state Fig. 8th. Limiter rod Fig. 9: Limiter disc Fig. 10: Inner spring Fig. 11: Mainspring Fig. 12: Working tube Fig. 13: Blockers Fig. 14: Working tube Fig. 15: Limiter disc (welded) Fig. 16: Limiter disc (screwed) Fig. 17: Center tube

As shown in Fig. 1, the system contains 8 springs, arranged symmetrically to the left and right of the blocker (5). The following should be noted according to their dimensions: inner spring (7), main spring for 1 (8), main spring for 2 (9). The blocker (5) is connected to the center tube (1) via the block attachment (5a). The limiter rod (6) is fixed in the blocker (5) or is loose, depending on the design.

The tailpipe with pull hook (12) shown in Fig. 3 is fixed by the pipe split pin (4) or the screw (15). Both act on the tailpipe (12) via the closure sleeve (13). At the end of the closure sleeve (13) the counterpart, pull loop, etc. on the vehicle can be hooked into the opening provided by the design.

The limiter rod (6) shown in Fig. 8 has a thread on one side for the screwed limiter disc (Ha) and on the other side a plug-in option for the welded limiter disc (11).

The different variants of the limiter discs (11, Ha) are shown in Figures 9, 15 and 16.

Fig. 17 only shows the working tube (2), which represents the fastening options for the blocker (5 a). This can be connected to the working tube (2) using rivets or screws, so that the central position of the working tube (2) in relation to the blocker (5) is always ensured.

Work process: Start-up

Spring-loaded tow bar: Rigid guide bar. When starting off, both working tubes (2) pull apart towards the vehicles, supported by a pre-tensioned spring (8) until the compressed springs (7, 9) stop on the limiter disc (11), thus enabling a smooth start. As soon as the tow truck is rolling and the starting jolt has reduced, the working tubes return to their original position.

Starting: With movable guide rod

When starting off with a movable guide rod, the same process is repeated as with a rigid guide rod; in addition, the tension on the front working tube after the springs (7, 9) have stopped is compressed by the limiting rod, which compresses the springs (8) pointing towards the towed vehicle and then the spring (7), which enables an even smoother start. The disadvantage of the guide tube required as a result is its higher weight.

Main and inner springs double the length. All outer springs must be pre-tensioned.

Adapters for other makes are provided (round + square pipes).

Installation of the system:

Start with the working tube (12), then the limiter rod (6) with limiter disc (11), then the springs follow in the order shown in the drawing, e.g. (9) and (7). Now the working tube (2) is pushed over it.

The limiter rod (6) is guided through the hole, followed by the other springs (7, 8). Next comes the blocker (5). Depending on the design, the blocker (5) is fixed to the limiter rod or provided with a guide.

Braking sequence:

When braking, the working tubes (2) press the springs, which are of different lengths, together. Since during braking the pre-tensioned spring (8) increases the damping first and the spring (7) only after half the spring travel, this results in a soft braking process that corresponds to the speed.

List of reference symbols:

D Center tube (guide tube) 2) Working tube 3) Ring amplifier 4) Hole for pipe cotter pin 5) Blockers 5a) Block fastening 6) Limiter rod 7) Inner spring for 8. + 9. 8th) Mainspring to 1 9) Main spring to 2. 10) End piece disc with hole for 6. &Pgr;) Limiter disc (welded) Ha) Limiter disc 12) Tailpipe with tow hook 13) Closure sleeve 14) Pipe cotter pin 15) Screw (inserted) 16) Mounting for inner spring (blocker) 16a) Mounting for inner spring (working tube) 17) Elastic buffer

Claims (6)

Konrad Holtermann 298 16 329.2 Große Düwelstr. 15 a 30171 Hannover Protection claims: 1) Device for towing motor vehicles, characterized by the combination of the following features: a) Rigid tailpipes (12) establish contact with the towed vehicle or the towing vehicle. b) A central or guide tube, which is held in the middle by the blocker (5), guides the working tubes (2). c) Springs (7, 9) are held by limiter disc (11 or Ha) and end piece disc (10). The middle area of the guide tube (1) accommodates the working springs (7, 8) to absorb the pressure energy, e.g. when the towed vehicle drives up. 2) Device for towing motor vehicles according to claim 1, characterized in that
that the guide tube (1) has at least 2 block fastening options. 3) Device for towing motor vehicles according to claims 1 and 2, characterized in that
that the blocker (5) is attached alternatively with rivets or screws. 4) Device for towing motor vehicles according to one or more of claims 1-3, characterized,
that the loaded pipes are preferably made of carbon steel. 5) Device for towing motor vehicles according to one or more of claims 1-4, characterized,
that the loaded pipes are made of hard aluminium. 6) Device for towing motor vehicles according to one or more of claims 1-5, characterized, that the spring system used (8 pieces) is adapted to the type and weight of the vehicle to be towed.