Lifts

Abstract

A lift system for mounting on a vehicle comprising: a platform 10; a base 12; upper 14 and lower 16 lifting arms connecting the platform 10 to the base 12; and a hydraulic actuator (32, Fig. 2) connec

Description

Field of the invention The present invention relates to lifts for wheelchair users, and in particular to lifts for mounting on vehicles. Background to the invention Wheelchair lifts which can be mounted on vehicles are well known and many of them are arranged to be stowed under the floor of the vehicle, and then powered out and unfolded into a deployed condition in which they can be raised and lowered in use. The lift platform is generally supported on two pairs of support arms, each pair comprising an upper and a lower support arm, connected to the vehicle at their inboard ends and to the lift platform at their outboard ends, forming a parallelogram configuration, with a hydraulic actuator connected between the inboard end of tire lower support arm and the outboard end of the upper support ami, so that extension of the hydraulic actuator raises the lift. An example of such a lift is shown in GB 2488921A. Each of the opposite ends of the hydraulic actuator is typically pivotably connected to a bracket, which may be in the form of a fork, which in turn is welded to the upper or lower support arm. The height of the lift in the fully raised position, which corresponds to the fully extended condition of the hydraulic actuators, is generally fixed. This means that adjustment of that fully raised position is typically achieved by adjusting the hydraulic cylinder, which generally requires the hydraulic cylinder to be stripped down and spacers inserted into it or removed from it. This can be a problem with lifts for personal use, community transport and minibuses, as well as coaches where the cost of keeping the vehicle off road and of the equipment needed for adjustment, and therefore the cost of conventional adjustment of the hydraulic cylinder, is particularly high. Summary of invention The present invention provides a lift system for mounting on a vehicle. The lift system may comprise a platform and a pair of lifting arms arranged to connect the platform to the vehicle. The lifting arms may comprise an upper lifting arm and a lower lifting arm. A hydraulic or other actuator may be connected between the upper and lower lifting arms and be operable to move the lift platform between a fiilly raised position, in which the hydraulic actuator is fully extended, and a lowered position. The hydraulic actuator may be connected to one of the upper and lower arms by means of and adjustable connection which is adjustable to adjust the fully raised position of the platform. The adjustable connection may comprise a bracket which is mounted on said one of the lifting amis, and to which the actuator is pivotably connected. The position of the bracket on said one of the lifting arms may be adjustable. Said one of die lifting arms may have a plurality of mounting holes formed in it. The mounting holes may be spaced along the lifting arm. The bracket may comprise mounting means which can be aligned with different combinations of the mounting holes thereby to mount the bracket in different positions on said one of the lifting arms. The lift system may further comprise a further pair of lifting arms, the further pair of lifting arms also comprising an upper lifting ami and a lower lifting arm, and a further hydraulic actuator connected between the upper and lower lifting arms, wherein the further hydraulic actuator is connected to one of the further pair of lifting arms by means of an adjustable connection. The lift system may further comprise any one or more features of the preferred embodiments of the present invention, as will now be described by way of example only with reference to the accompanying drawings. Brief description of the drawings Figure 1 is a side view of a lift according to an embodiment of the invention; Figure 2 is a side view of a pair of lifting arms forming part of the lift of Figure 1; Figure 3 is an enlargement of part B of Figure 1; Figure 4 is a perspective view of two upper lifting arms forming part of the lift of Figure 1; Figure 5 is an enlargement of part G of Figure 4; and Figure 6 is a perspective view of a support bracket forming part of the lift of Figure 1. Description of the Preferred Embodiments Referring to Figures 1 and 2, a lift system for a vehicle comprises a lift platform 10 connected to a base 12 by two pairs of lifting arms 14, 16. Hie lift platform (which is mostly hidden from view in Figure 1) typically has handrails 18 at its outboard end, and a bridge plate 20 at its inboard end. The handrails 18 and the bridge plate 20 may be arranged to fold flat against the lift platform 10, so that the base 12, and the rest of the lift assembly with it, can be retracted into a housing 22, which is typically located under the floor of the vehicle. Each pair of lifting arms comprises an upper arm 14 and a lower arm 16. The upper and lower arms 14, 16 each have their inboard end 24, 26 pivotably connected to the base 12 and their outboard end 28, 30 pivotably connected to the lift platform 10. A hydraulic actuator 32 is arranged to act between each pair of lifting arms 14, 16 to raise and lower the lift platform 10. As can best be seen in Figure 2, the inboard end of the hydraulic actuator 32 is connected to the lower lifting arm 16, towards its inboard end 26, for example by means of a mounting bracket 34. This bracket 34 may for example be welded or bolted to the lower lifting arm 16. The other end of the hydraulic actuator 32 is connected to the upper lifting arm 14, towards its outboard end 28, for example by means of a further bracket 36 which is in the form of a fork as will be described in more detail below. Referring to Figures 3 and 4, the two upper lifting amis 14, which are on opposite sides of the lift platform 10 and both shown in Figure 4, may each comprise a main part 14a which has a generally inverted U-shaped cross section, having a top wall 40, an inner sidewall 42, and an outer sidewall 44. Connecting lugs 14b may be fixed to each end of the main part 14a and have holes through allowing the pivotal connections to the base 12 and lift platform 10. The outer sidewall 44 preferably extends downwards below the bottom of the inner sidewall 42, to just below die bottom of the lower lifting arm 16. It may therefore cover the gap between the upper and lower lifting arms 14, 16. The top wall 40 may have, near the outboard end 28 of the upper lifting arm 14, a row of fixing holes 50 though it. These may be simply drilled through the top wall 40 of the upper lifting arm, or, as shown in Figures 3 and 5, tiiey may be formed in a separate insert 52 which is fitted to the main part 14a of the upper lifting arm 14, for example below an opening 54 in the top wall 40 of the upper lifting arm which exposes the fixing holes 50. If an insert 52 is used, it may be welded or bolted to the main part 14a of the upper lifting arm 14. A connecting bracket or fork 60 may be arranged to connect the outboard end of the hydraulic actuator 32 to the upper lifting arm 14. The connecting fork 60 may for example have two lugs 62 projecting from one end which define a gap 64 therebetween, with aligned holes 66 formed through the lugs 62 in the horizontal direction. Referring back to Figure 3, these holes 66 may be arranged to receive a pin 68, and a lug 70 on the outboard end of the actuator may be arranged to fit between the lugs 62 on the fork 60 and also have a hole through it, through which the pin 68 can also extend to support the end of the actuator in the fork 60, such that it can pivot relative to the fork as the lift is raised and lowered. A number of fixing holes 72, for example three as shown, may be formed through the fork 60. These fixing holes 72 are preferably equally spaced from each other, and also of equal spacing to the fixing holes 50 in the upper lifting arm 14. However there are more fixing holes 50 in the upper lifting arm 14, for example seven as shown. This means that the fixing holes 72 in the fork 60 can be aligned with any of a number of different groups of the fixing holes 50 in the upper lifting arm 14, corresponding to a number of different positions of the fork 60 along the lifting arm 14. The fork 60 can be secured in any one of those positions by fixings 74 which extend through the selected group of fixing holes 72 in the upper lifting arm and into the fixing holes 72 in the fork 60. A cover 76 may be arranged to fit over the opening 54 in the upper lifting arm 14 and may be removably secured in place by fixings 78 which engage in cover fixing holes 80 in the lifting arm 14. In operation, in the embodiment shown in the drawings, when the lift is being raised, the actuators 32 are extended until they reach their maximum length at which point the lift platform is in its fully raised position and cannot be raised any further. Typically in the fully raised position, the lifting anus 14, 16 are inclined upwards from their inboard ends to their outboard ends, and the lift platform is level with the floor of the vehicle, which is above the housing 22. The bridge plate 20, which is lowered when the lift is in the fully raised position to bridge the gap between the lift platform 10 and the vehicle floor, can accommodate a slight difference in height between the lift platform 10 and the vehicle floor. However if the lift is to be installed in a number of different vehicles, some adjustment of the height of the lift platform, relative to the housing 22, when the lift is in the fully raised position is desirable. In the arrangement shown, this adjustment can simply be provided by adjusting the position along the upper lifting arms 14 to which the outboard ends of the hydraulic actuators are connected. It will be appreciated that the details of the embodiment shown may be varied whilst still 5 falling within the scope of the present invention. For example the number, position and shape of the fixing holes 50, 72 may vary, the shape and structure of the fork or bracket 60 may also vary, or the fork may be omitted altogether if a different fixing method is used to adjustable connect the hydraulic actuator 32 to the upper lifting arm. Instead of, or as well as, being adjustably connected to the upper lifting arm, the actuator may be adjustable 10 connected to the lower lifting arm, for example using similar methods to those described above for the upper lifting ami.

Claims

1. A lift system for mounting on a vehicle. The lift system may comprise a platform and a pair of lifting arms arranged to connect the platform to the vehicle, the pair of lifting amis comprising an upper lifting ami and a lower lifting arm, and a hydraulic actuator connected between the upper and lower lifting arms and operable to move the lift platform between a fully raised position, in which the hydraulic actuator is fully extended, and a lowered position, wherein the hydraulic actuator is connected to one of the lifting amis by means of an adjustable connection which is adjustable to adjust the fully raised position of the platform.

2. A lift system according to claim 1 wherein the adjustable connection comprises a bracket which is mounted on said one of the lifting arms, and to which the actuator is pivotably connected.

3. A lift system according to claim 2 wherein the position of the bracket on said one of the lifting arms is adjustable.4 A lift system according to claim 3 wherein said one of the lifting arms has a plurality of mounting holes formed in it, the mounting holes being spaced along the lifting arm, and the bracket comprises mounting means which can be aligned with different combinations of the mounting holes thereby to mount the bracket in different positions on said one of the lifting arms.

5. A lift system according to any preceding claim further comprising a further pair of lifting arms, the further pair of lifting arms also comprising an upper lifting arm and a lower lifting arm, and a further hydraulic actuator connected between the upper and lower lifting amis, wherein the further hydraulic actuator is connected to one of the further pair of lifting arms by means of an adjustable connection.

Images