TEST RIG

Abstract: A test rig (10) for assessing the performance of a force generating actuator (11) in which a beam (20) is angularly displaceable about a fulcrum (12) from a position of rest. The test rig further comprising mounts (13) for mounting the actuator to apply a turning force to the beam, and resistance means (30) acting on the beam in opposition to the force. The resistance means includes a plurality of resistant elements (E1, E2, E3, E4, E5 and E6), which are progressively engaged by the bean as it is displaced from the position of rest to provide a progressively increasing resistant force.

Description: TEST RIG The present invention relates to test rigs for assessing the performance of a force generating actuator, and in particular for assessing the performance of force generating actuators used to effect powered closure of an automotive vehicle door. Typically such test rigs have assessed the performance of the actuator by requiring the actuator to overcome a known constant load. It is an object of the present invention to provide an improved form of test rig which allows a progressive increase in the force required to be overcome by the actuator. It is a further object of the invention to provide a test rig which is simple to manufacture, use and maintain, and in which the force to be overcome can be easily changed to suit different test conditions. Thus according to the present invention there is provided a test rig for assessing the performance of a force generating actuator, including a beam angularly displaceable about a fulcrum from a position of rest, means for mounting the actuator to apply a turning force to the beam, and resistant means acting on the beam in opposition to said force; characterised in that the resistant means includes a plurality of resistant elements which are progressive engaged by the beam as it is displaced from the position of rest to provide a progressively increasing resistant force. The present invention will now be described, by way of example only, with reference to the accompanying drawings in which :- Figure 1 is a view of a test rig according to the present invention in a position of rest; Figure 2 is a view of the test rig of Fig.1 in which the actuator has applied a partial turning force, and; Figure 3 is a view of test rig of Figure 1 in which the actuator has applied a full turning force. Figure 4 is a graph showing the resistant force exerted on the actuator during its range of travel. With reference to Figures 1 to 3 of the accompanying drawings there is illustrated a test rig 10 comprising a base 14, a mounting means 13 rigidly secured to the base 14 and a fulcrum mounting 15, also rigidly secured to the base 14. The test rig further comprises a beam 20, mounted in an angularly displaceable fashion on fulcrum mounting 15 via fulcrum 12, and resistant means 30. Beam 20 comprises a first arm 21 on one side of the fulcrum 12 and a second arm 22 on the other side of the fulcrum 12. First arm 21 includes a plurality of pins 23 regularly spaced apart along the beam with each pin projecting laterally from the beam. Second arm 22 includes an abutment 23 for contact by an actuator 11. When the test rig is in use, the actuator 11 is mounted on mounting means 13. The resistant means 30 includes (in this case) six resistive elements El- E6. Resistive element El includes an elongate portion PI defining a vertical slot, and a weight Wl fixed to the lower part of elongate portion PI. The other resistive elements E2-E6 each have respective elongate portions P2-P6 and respective weights W2-W6. In this example elongate portion PI defines the shortest vertical slot and elongate portions P2-P6 progressively define longer vertical slots. Furthermore, in this example weights W1-W6 are equal. Consideration of Figure 1 , which shows the beam 20 in a position of rest, shows that each pin 23 sits in a respective slot of the respective elongate portion of the associated resistive element. Furthermore each pin 23 is remote from the upper end portion of the slot of the corresponding resistive element with the beam in this position. Thus it is apparent that each resistive element has a lost motion connection with the beam, and in this case for example the lost motion connection of resistive element E6 is greater than the lost motion connection of resistive element El with the beam. Operation of the test rig is as follows: Force generating actuator 11 is mounted on the mounting means 13 and is operated such that actuator rod 11A contacts abutment 24 and causes the beam to rotate in a clockwise direction when viewing Figure 1. Initially the actuator only has to overcome the resistant force caused by the centre of gravity G of the beam being off-set relative to the fulcrum 12. Subsequently the pin 23 associated with the elongate portion PI of resistive element El contacts the upper portion of its corresponding slot resulting in weight Wl being lifted off base 14. Further operation of actuator 11 causes each weight W2 to W6 to progressively lift off base 14 requiring actuator 11 to produce a progressively increasing turning force to overcome the progressively increasing resistant force of the resistant means 30. Figure 2 shows a resistive force being provided by resistive elements El, E2, and E3 and figure 3 shows a resistive force being provided by all the resistive elements El to E6, It is apparent that it is easy to change the test rig to simulate different operating conditions, for example:- a. One or more resistive elements can be disconnected from the beam. b. The weights of one or more resistive elements can be easily altered. c. The amount of the lost motion connection of one or more resistive elements can be varied. d. Provision may be made for adjusting the position of one or more of pins 23 longitudinally of the beam. Furthermore not only does the rig allow easy alteration of the resistant force to be overcome by the actuator, but also the rotational inertia of the beam and associated resistive elements about fulcrum 12 can be varied. For example a resistive element of weight X acting at distance Y from the fulcrum 12 produces the same resistive force as a resistive element of weight half X acting at distance 2Y from the fulcrum 12, but the rotational inertia about fulcrum 12 is two times less in the former case than in the latter case. Thus it is possible to use the rig to simulate not only the force required to close an automotive door but also to simulate the inertia of that door. Additionally adverse closing conditions of a door can be simulated such as wind forces on the door or when the vehicle is parked on a slope. In further embodiment of the invention one or more of the weights Wl to W6 could be replaced by a chain connected at one end to the corresponding elongate portion PI to P6 such that rotation of the beam causes the chain to progressively lift off the base 14. Figure 4 is a graph of the resistant force exerted on the actuator during its range of travel in a typical test cycle using a rig, simulating the force needed to close a door by powered rotation of the latch bolt claw from its first engagement with the related striker (first safety position) to fully latched involving compression of the door weather seals.

Claims: CLAIMS 1. A test rig for assessing the performance of a force generating actuator including a beam angularly displaceable about a fulcrum from a position of rest, means for mounting the actuator to apply a turning force to the beam, and resistant means acting on the beam in opposition to said force; characterised in that the resistant means includes a plurality of resistant elements which are progressively engaged by the beam as it is displaced from the position of rest to provide a progressively increasing resistant force. 2. A test rig as defined in Claim 1 in which the beam includes an abutment for applying a turning force to angularly displace the beam about the fulcrum. 3. A test rig as defined in Claim 2 in which the fulcrum is positioned between the resistant means and the abutment. 4. A test rig as defined in any previous claim in which the resistant means includes a plurality of weights, at least one of which does not create a resistant force when the beam is in the position of rest and does create a resistant force when the beam is angularly displaced from the position of rest. 5. A test rig as defined in Claim 4 in which the said at least one weight is connected to the beam by a lost motion connection. 6. A test rig as defined in Claim 5 in which the lost motion connection is in the form of a pin on one of the beam or weight slidable in a slot of the other of the beam or weight. 7. A test rig as defined in any previous claim in which the centre of gravity of the beam is not coincident with the fulcrum. 8. A test rig as defined in any previous claim in which the resistant means includes a chain which progressively increases the resistant force during at least part of the movement of the beam from the position of rest to a test position. 9. A test rig as defined in any preceding claim in which the resistant means is arranged to simulate the progressive increase in force necessary to effect door closure from a first safety position at which a claw or other bolt of a door latch initially engages a contacting striker of a door aperture. 10. A test rig substantially as hereinbefore described with reference to or as shown in figures 1 to 3 of the accompanying drawings. 11. A test rig as defined in any previous claim including an actuator, said actuator being a latching actuator for effecting powered closure of a vehicle door. 12. A method of assessing the performance of a force generating actuator comprising the steps of mounting the actuator in a test rig according to any one of claims 1 to 11, and operating the actuator to angularly displace the beam about the fulcrum. 13. An actuator when tested by the method of Claim 12.

Inventors: FISHER SYDNEY EDWARD, FISHER, SYDNEY, EDWARD
Applicants: FISHER SYDNEY EDWARD, MERITOR LIGHT VEHICLE SYS LTD, FISHER, SYDNEY, EDWARD, MERITOR LIGHT VEHICLE SYSTEMS (UK) LTD.
Application year: 1999
Main classification: G01M13
IPC codes: G01M13, G01M19