LANGOLF, Odd (Korntrøvegen 24, Hommelvik, N-7550, NO)
114211/JH
P a t e n t c l a i m s
1. A surge brake for semi trailer (10) with a pivotable trailer connection
5 secured in a holding apparatus (2), where the holding apparatus (2) is slideably secured in relation to the trailer (10); and where a spring apparatus (9) biases the holding apparatus (2) towards a forward position in relation to the trailer (10), c h a r a c t e r i z e d i n : a mechanical connection with a pulling body (4) connected between the holding o apparatus (2) and a brake for the trailer (10) for transferring a pulling force that is imposed on the pulling body during a shift of the holding apparatus (2) backwards on the trailer in relation to a normal driving direction to the brake.
2. The surge brake apparatus according to claim 1 , where the mechanical 5 connection includes a pivot arm (5) with a pivotal support (6) and a first side at one of the side of the support (6) and another side at the other side of the support (6), where the holding apparatus (2) is pivotally connected to the first side; and the pulling body (4) is a pulling rod with two ends, where one end is connected to the other side of the pivot arm (5) and the other end is adapted for mechanical 0 connection to the brake on the trailer (10).
3. The surge brake apparatus according to claim 1 , where the pulling body (4) includes a wire in guides.
5 4. The surge brake apparatus according to claim 1 , further including two longitudinal guide bodies (1) parallel extending and secured to the trailer (10); and guides (3) rigidly secured in the holding apparatus (2) and slideable connected in the longitudinal guide bodies (1).
0 5. The surge brake apparatus according to claim 1 , further including two longitudinal guide bodies (1) parallel extending and rigidly secured to the holding apparatus (2); and guides (3) rigidly secured to the trailer (10) and slideable secured to the longitudinal guiding bodies (1),
6. The surge brake apparatus according to claims 4 or 5, where the distance between the two longitudinal guiding bodies is between 60 cm and 80 cm. |
Surge brake for semi trailer
The present invention concerns a surge brake for semi trailer.
Common trailers for small loads, and that uses common tow hitch, and that includes a trailer ball hitch, is encumbered with some problems, in particular when the load on the trailer is considerable. Trailer hitches of this type is today attached to everything from motorbikes, small cars and upwards. The load on the trailer hitch is today normally limited to 125 kg, and this leads to trailers of this type being very sensitive to how the trailer is loaded. Wrongly loaded trailers that results in a greater load on the trailer hitch can be dangerous because the trailer will reduce the load on the front wheels of the vehicle, and the road holding of the vehicle will be considerably reduced. Furthermore such a load will make the friction in a surge brake excessive such that the brake not will operate satisfactory.
Similarly this is a problem if the trailer is loaded such that the trailer hitch is loaded upwards, and this can result in the load on the rear wheel of the vehicle to become too small, with a corresponding reduction of the road holding towards the surface and the driving ability.
Accordingly there are today semi trailers or swan neck trailers for pickups, trucks and tractors.
On such trailers, the trailer hitch is placed over the rear wheels of the tractor vehicle, and this makes the trailer considerable less sensitive in terms of load location, as the tractor vehicle can carry considerable parts of the load without the balance of the vehicle being affected in the same extent.
Similarly, the load can be placed over the driving wheels such that the driving wheels get a considerably better grip, and this can be of major importance in particularly when it is slippery, for instance during winter driving.
Such vehicle trailer combinations usually include a turning plate, turret plate or fifth wheel coupling, where a kingpin goes into the turret plate.
It also exist such systems where a pulling hitch corresponding to the one used for trailers described above is included. Braking systems for this kind of trailers are normally complex and usually include the use pneumatic brakes, hydraulic brakes or electric actuators. This makes the trailers expensive to manufacture and complicated to use.
Braking systems for this type of trailer is for instance shown I US 4,840,256 where a trailer hitch for attachment to a truck body on a vehicle may include a hitch ball attached to a sliding block that is moveably fixed to a carrying plate. The sliding block can thereby move in relation to the carrying plate that is rigidly attached to the vehicle. The sliding block is connected to a braking cylinder that imposes pressure to hydraulic brakes on the trailer. Thereby the trailer must be connected to the brake cylinder on the vehicle with a hydraulic line. When the trailer is to be moved from the vehicle, it is suggested to unscrew the brake cylinder such that the brake cylinder remains on the trailer such that it not is necessary to disconnect the hydraulic system from the trailer.
In US 2,051 ,522 it is shown a corresponding system where a trailer hitch is connected to a hydraulic cylinder that supplies hydraulic pressure between the vehicle and the trailer and to the wheel of the trailer through lines.
In US 3,834,767 it is shown a corresponding system, but where a common connection or kingpin is attached to a plate that is slideable placed on a trailer. The plate is connected to a hydraulic brake through a servo brake system.
The shown systems all include complicated and expensive systems that not easily can be used in particular on smaller semi trailers. Accordingly it is a purpose of the present invention to provide a braking system for semi trailers where it can be used components that today are normally used on trailers with a surge brake, but where the above mentioned problems with this type of trailers are omitted.
According to the present invention it is possible to make a semi trailer with the economic advantages of a common trailer.
Furthermore it is an object of the invention to provide a surge brake that is allowed to slide in relation to the trailer even if the load on trailer hitch is considerable.
Surge brakes for trailers according to the invention include a pivotable trailer fixture. Such a fixture typically includes a kingpin fixture or a common trailer hitch. This pivotable securing mechanism for securing the trailer to a vehicle is attached in a holding apparatus. The securing mechanism, for instance the kingpin, is preferably centrally and symmetrically placed on the holding apparatus.
The holding apparatus is slidable secured in relation to a frame on the trailer and can in itself be shaped as a steel frame, a rigid plate or in any other
way. A spring device biases the holding apparatus towards a forward position in relation to the trailer. With forward, it is meant a position towards a normal direction of motion for the trailer.
A mechanical connection with a body adapted for pulling is connected between the holding apparatus and a brake for the trailer for transferring a pulling force that is imposed to the pulling body when the holding apparatus is moved backwards on the trailer in relation to a normal driving direction and transfers this force to the brake. The pulling body is typically a rod or wire. A transfer mechanism to transfer the pulling force over height differences on the trailer may include a rotating shaft with an arm for fixing pulling bodies at each end.
The mechanical connection may include a pivot arm with a bearing and a first side on one of the sides of the bearing and a second side on the other side of the bearing. The holding apparatus is in this case revolving connected to the first side and the pulling body constitutes of a pulling rod with two ends, where one end is connected to the other side of the pivot arm and other end is adapted for mechanical connection to a brake on the trailer. Alternatively the pulling body may include a wire in guides in terms of pulleys, bowden cables or in other way.
The sliding fixture may include two longitudinal guiding bodies parallel extending and secured to the trailer. One of the bodies may be rigidly secured to the trailer and the other may be floatingly secured to prevent deformations of the trailer from imposing unnecessary forces on the guiding bodies, guides and the holding body. The guides can be rigidly connected to the holding apparatus and can be slideable secured to the longitudinal guiding bodies. The securing mechanism, for instance the kingpin, may be centrally and symmetrically placed in relation to the guides such that a distance between the guides, for instance four guides, and the securing mechanism is substantially the same for all the guides. It can of course be used a higher number guides, for instance six, and then the distance between two of the guides will be somewhat less.
The two longitudinal guide bodies may alternatively be parallel extending and rigidly secured to the holding apparatus and guides, may be rigidly secured to the trailer and slideable secured in the longitudinal guide bodies (1). The distance between the two longitudinal guide bodies may be between 60 cm and 80 cm. Short description of the enclosed figures:
Fig. 1 shows an embodiment of the invention from the front; and Fig. 2 shows an embodiment of the invention on fig. 1 from above.
Detailed description of an embodiment of the invention: From figure 1 it is shown a holding apparatus 2 holding a securing mechanism 11 for attachment to a vehicle. The dimensions that are suggested are intended for a trailer with a total weight up to 3500 kg. In the shown embodiment, the securing mechanism includes a kingpin, for instance a 2" kingpin. The kingpin is welded to a holding apparatus 2. Furthermore it is shown to guides 3 rigidly secured at each side of the holding apparatus 2 at a distance that ensures good stability for the holding apparatus 2 in relation to a trailer. In the shown embodiment it is placed low friction guides 3 in steel cylinders rigidly welded to the holding apparatus 2. The low friction guides 3 are self-cleaning and lubricant free guides placed around and slidingly fixed around the longitudinal guiding bodies 1 or bolts with a diameter of 40 mm. 40 mm is shown as this is the first standard measurement of bolts (guide bodies) and guides above what is necessary to achieve the necessary rigidity, fracture strength and fatigue resistance. The distance between the guide bodies in the shown embodiment is 70 cm.
The guiding bodies 1 may be of chromated stainless steel. The longitudinal guiding bodies are shown as cylindrical rods. It is an advantage that the guiding bodies has a shape that prevents dirt and loose matter to collect on the bodies, and instead will slide off. A different guiding body could for instance be a square rod placed with a corner upwards such that the sides forms 45° in relation to a horizontal line to prevent dirt and loose matter such as sand and similar matter to remain of the body.
On figure 1 it is also shown a hole for the pulling rod, shown on figure 2. One of the guiding bodies 1 are preferably rigidly secured to the trailer frame and the other guide body 1 is floatingly secured or supported such that it is allowed a certain motion between the frame on the trailer and the other guide body. The purpose of this is that deformations or tensions in the trailer not should be transferred to the guides in the holding apparatus as this would lead to increased friction, wear reduced or wrong operation as a result. Without this
system, the load of the frame may lead the guiding bodies 1 out of parallel alignment.
From figure 2 the invention according to figure 1 is shown from above. The figure shows how the holding apparatus 2 is slideable secured to the trailer 10
5 through longitudinal guide bodies 1 rigidly secured to the trailer 10, and guides 3 rigidly secured to the holding apparatus 2, and slideable secured to the longitudinal guiding bodies 1. A pivot arm 5 is rigidly supported in the trailer 1 and has a pivot point 6 where the pivot arm 5 is supported. On the other side of the pivot arm 5, it is pivotally secured in the holding apparatus 2 through a pulling rod o 12 between the holding apparatus 2 and the pivot arm 5. A pulling rod 4 is pivotally secured at one side of the pivot arm in a pivot point 7. A spring device 9 between the slideable holding apparatus 2 and the trailer 10 biases the holding apparatus 2 towards a forward position. The holding apparatus 2 holds a centrally placed kingpin 11. The pulling rod 4 is connected to the brakes on the trailer wheels (not s shown) in an ordinary way. The pulling rod 4 is shown a rod, but it could also have been a wire or another suitable body.
During braking of a vehicle holding the trailer 10 through kingpin 11 , the kingpin 11 will press the holding apparatus 2 against the bias of the spring device 9 such that the holding apparatus 2 slides along the longitudinal guide bodies 1 o through the guides 3 such that the pivot arm 5 pivots about its journal 6 on the trailer, and such that the pivot arm 5 pulls the pulling rod 4 for actuating the brakes in an ordinary way.
For securing the vehicle and the trailer, it is shown a kingpin for being attached to a turning plate or a fifth wheel coupling, but any pivotal connection 5 between the vehicle and the trailer could be used.
In the shown embodiment, the longitudinal guide bodies 1 are shown as cylindrical rods, but these could have been any kind of suitable shaped bodies as long as these fit to the guides 3. It is however an object that the distance between the guide bodies 1 and the guides 3 is as great as possible to reduce the friction o between the guides 3 and the longitudinal guiding bodies 1 , as this distance will affect how much the holding apparatus 2 is inclined in relation to the trailer 10 to thereby create unnecessary friction.
The spring device 9 may also include a shock absorber to ensure that it is not created fluctuations between the holding apparatus 2 and the trailer 10. The spring device 9 may be a standard component well known within the art or any component that will impose a spring action. The spring device may be a standard braking damper for a surge brake. Other examples of such apparatuses may include pneumatic or hydraulic systems.
The guides 3 may be of a synthetic material with low friction in relation to the longitudinal guiding bodies 1 such that the holding apparatus 2 easily can slide back and forth in relation to the trailer 10 even under considerable load. Suitable materials may be nylon or teflon. It could also be metal against metal, but this would necessitate considerable use of lubricants. Lubricants may be a disadvantage as these will encourage dirt to get stuck and will necessitate using protecting bellows around the guiding bodies 1 etc.
The material of the guides must also have a sufficient wear resistance as the load on the guides will be considerable.
The rods or guiding bodies 1 will also have a diameter that ensures that the surface pressure between the guiding bodies 1 and the guides 3 not is excessive. This is to ensure sufficiently low friction and low wear on the guides. The distance between the guiding bodies will be sufficient such that a considerable stability is ensured. The holding body 2 will typically be movable a distance that ensures sufficient deflection on the pivot arm and accordingly such that the brakes work as intended.
Dimensions of the pivot arm and the distance between where the pivot arm is secured in the pulling rod from the holding apparatus, the pulling rod to the brakes and how it is secured to the trailer will be dimensioned according to the construction of the brakes, weight of the trailer etc. Alternatively, the attachment of pulling rods to the pivot arm may be adjusted to adapt the brakes to the load on the trailer. This will also be affected by the stiffness of the spring device. With a corrected adjustment will a surge brake to a great extent adjust itself as the effect of the brakes will be affected by the weight on the trailer.
In an alternative embodiment the transfer between the holding apparatus 2 for the kingpin be through a bowden cable instead of the pivot arm and pulling
rods. However a bowden cable is more exposed to wear, malfunction, jamming, corrosion, dirt etc. and will therefore in many cases be a less suitable choice.
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