LADDER RAMP

Abstract: A ladder ramp (5) designed for rapid lowering of a ladder (6) which in a position of readiness is lying upon the ramp, which may in turn be mounted on a rescue vehicle (20) or may be placed in a building structure. A pivot frame (4) is rotatably connected to a base structure (2), and at least one dampening means (3) for the pivotal movement functions between the base structure (2) and the pivot frame (4). There is also included a sliding frame (1) which can slide in parallel with the pivot frame (4) and at least one dampening means for the sliding movement that in turn functions between the sliding frame (1) and the pivot frame (4). A releasable locking device holds the sliding frame (1) in the position of readiness.

Description: LADDER RAMP. The present invention relates to a ladder ramp designed for rapid lowering of a ladder which in a position of readiness is lying upon the ramp. Such a ladder ramp is particularly intended for rescue purposes, to be used, for example, in the rescue services such as on a fire engine. However, the ladder ramp could conceivably be used in building structures, also, to be in preparedness if emergency situations should ' arise. As mentioned, the present ladder ramp has been developed with a view toward rescue operations where the time required to rig the equipment into place can be of critical importance. Thus, there will always be a need for equipment which can bring rescue equipment more rapidly from a position of readiness into operational position. It is preferable that this be done as automatically as possible, i.e., with the fewest possible manual operations. This is achieved with the present ladder ramp that is capable of rapidly and easily bringing a ladder lying in readiness on the ladder ramp into position for further handling by a crew. An example of such a ladder is shown in NO patent application no. 891964. This is achieved with a ladder ramp of the kind mentioned above, which is characterized by a pivot frame rotatably connected to a base structure, at least one dampening means for the pivotal movement that functions between the base structure and the pivot frame, a sliding frame capable of sliding in parallel with the pivot frame, at least one dampening means for the sliding movement that functions between the sliding frame and the pivot frame and a releas- able locking device which in the starting position- holds the sliding frame in its mode of readiness. The actual sliding frame can well be in the form of a ladder, which has the advantage that, after the lowering of the ladder ramp, the crew is able to climb up onto the rescue vehicle to fetch equipment. The pivot frame can, as mentioned above, be attached directly to the vehicle or support structure, but there may ad¬ vantageously be included a base frame which in turn is secured to the base structure. It is advantageous to include a supporting block that is attached to the base structure or the vehicle and forms a resting surface and holder for the sliding frame at the forward edge when the ladder is in its position of readiness. The sliding frame may include support wheels at the forward edge thereof for contact with the supporting block. Although not a requirement, the sliding frame may advantage¬ ously form a gradient with the base structure or the base frame In the readiness position. This facilitates the lowering of the ladder, which will take place almost automatically with the aid of the intrinsic weight of the ladder and the sliding frame, together with the displacement of their center of gravity. To further reduce the friction between the sliding frame and the pivot frame, the pivot frame may with advantage be provided with rollers that engage with the sliding frame or with the side rails thereof. The various dampening means can constitute gas springs, gas dampers, or conventional shock absorbers. Other additional objectives, features and advantages will be apparent from the following description of the presently pre¬ ferred embodiment of the invention, provided for the purpose of description without thereby being limiting, and given in connection with the enclosed drawings, where: Figure 1 schematically shows a rescue vehicle onto which is mounted a ladder ramp according to the invention together with a ladder positioned thereon, Figure 2a-2c schematically shows three phases of the process of lowering the ladder from its readiness position. Figure 3a, 3b schematically shows the ladder ramp in closer detail, and Figure 4 shows in section the articulated connection between the base structure and the pivot frame. Reference is made to Figure 1, which shows a rescue vehicle 20 equipped with a ladder ramp 5 which is placed on the back of the truck and on top of the vehicle body. A ladder 6 lies on the ladder ramp 5 in readiness position up on the truck. The ladder ramp 5 comprises a pivot frame 4 rotatably connected to the truck itself or to a base structure 2. Between a fastening bracket 11 on the base structure 2 and the pivot frame 4 there is pivotably secured at both ends a dampening means 3. A sliding frame 1 lies in the pivot frame 4 and is slidable in relation thereto. As shown in Figure 3b, another dampening means 7 is placed in the pivot frame 4 and is intended to dampen the movement of the sliding frame 1. There is also included a releasable locking device 15 which in starting position holds the sliding frame 1 in Its mode of readiness. Figure 1 also indicates with dotted lines four different phases (A,B,C,D) in the process of lowering a ladder 6 by means of the ladder ramp 5. The lowering process is more clearly illustrated in Figures 2a, 2b and 2c. In the readiness position, the sliding frame preferably forms an angle of inclination ot with the base structure 2. On release of the locking device 15, the sliding frame 1 with the ladder 6 begins to move backwards due to the force of gravity. To facilitate this movement, the pivot frame 4, as also shown in Figure 3a, is equipped with rollers 9 that run within the side rails of the sliding frame 1. These side rails may in cross-section have a C-profile, like the side members of the ladder. In their backward movement the sliding frame 1 and the ladder 6 reach a point where their center of gravity passes the rotational axis 12 of the pivot frame 4, and the sliding frame 1 will then begin to swing down, bringing with it the ladder 6. As is clearly apparent from Figure 3b, a dampening means 7 between the pivot frame 4 and the sliding frame 1 serves to deaden the motion during the final phase of the return course of the sliding frame. Attached to the sliding frame is a stop means 16 for engagement with the dampening means 7. As an example, the motion can be dampened substantially during the final 30 centimeters of movement. The actual pivotal movement between the base structure 2 or a base frame 2b and the pivot frame is controlled by the dampening means 3. At the desired angle between the base structure 2 and the sliding frame 1 the pivotal movement is stopped, for example at maximum extension of the dampening means 3 or another limiting means (not shown). The ladder ramp may include a supporting block 10 secured to the base structure 2, which forms at the forward edge a surface on which the sliding frame rests at the same time as the frame and the ladder are held in place vertically, for example, during transport. For ease of movement in inserting or bringing down the ladder 6, the sliding frame 1 is equipped at the forward edge with support wheels 8. If the locking device 15 cannot be reached from the ground, it may be operated by means of, for example, a line pull. The sliding frame 1 may also be equipped at the rear edge with a pulling means, such as a line, to assist In bringing down the ladder ramp if the vehicle is, for example, placed with its front facing down a hill or if the gravitational force is not sufficient to initiate the sliding movement between the sliding frame 1 and the pivot frame 4. Figure 4 shows in closer detail the articulated connection between the base frame 2b and the pivot frame 4 and a roller 9 that rolls within the side rail of the sliding frame 1. The articulated connection between the base structure 2 or the base frame 2b and the pivot frame 4 is accomplished In the embodiment shown by means of a shaft journal 12 on both sides.

Claims: P a t e n t C l a i m s 1. A ladder ramp designed for rapid lowering of a ladder (6) which in a position of readiness is lying upon the ramp (5), c h a r a c t e r i z e d by a pivot frame (4) rotatably connected to a base structure (2), at least one dampening means (3) for the pivotal movement that functions between the base structure 2,2b) and the pivot frame (4), a sliding frame (1) capable of sliding in parallel with the pivot frame (4), at least one dampening means (7) for the sliding movement that functions between the sliding frame (1) and the pivot frame (4) and a releasable locking device (15) which in the starting position holds the sliding frame (1) in its mode of readiness. 2. A ladder ramp in accordance with claim 1, c h a r a c t e r i z e d i n that the actual sliding frame (1) is in the form of a ladder. 3. A ladder ramp in accordance with claims 1 - 2, c h a r a c t e r i z e d i n that the base structure is a base frame (2b). 4. A ladder ramp in accordance with claims 1 - 3, c h a r a c t e r i z e d i n that there is included a supporting block (10) attached to the base structure which forms a resting surface and holding means for the sliding frame (1) at its forward edge in the position of readiness. 5. A ladder ramp in accordance with claims 1 - 4, c h a r a c t e r i z e d i n that the sliding frame (1) comprises support wheels (8) for contact with the supporting block (10). 6. A ladder ramp in accordance with claims 1 - 5, c h a r a c t e r i z e d i n that the sliding frame (1) forms an angle of inclination α with the base structure (12) or the base frame (2b) in the position of readiness. 7. A ladder ramp in accordance with claims 1 - 6, c h a r a c t e r i z e d i n that there are provided rollers (9) on the pivot frame (4) that engage with the sliding frame (1). 8. A ladder ramp in accordance with claims 1 - 7, c h a r a c t e r i z e d i n that the dampening means or is/are a gas spring, a gas dajnper or conventional shock absorber.

Inventors: HEGGEN HANS, SKOGLUND ALF, HEGGEN, HANS, SKOGLUND, ALF
Applicants: RAUFOSS AS, RAUFOSS A/S
Application year: 1990
Main classification: E04G11
IPC codes: E06C5