BATTERY CASSETTE HANDLER
This invention relates to a battery cassette handler, for example for mounting on an electric motor driven vehicle, to simplify the replacement of a set of exhaustedbatteries by a recharged set, where the large number cf batteries necessary are assembled in a single module or "cassette" for mounting at one position on the vehicle chassis. A battery cassette could weigh about two and a quarter tonnes which is too much for a light-weight pallet lifting truck to be able to handle.
According to the present invention, a battery cassette handler comprises lifting cables and an actuator for the cables, brackets, and pins or other engagement means for supporting the cassette from the brackets when lifted into position. Preferably the cables are in flexible sleeves, the ends of which are fixed while one end of all the cables is connected to a common actuator, and at the other end the cables are connected to cassette engagement means. The actuator can be a pneumatic, or preferably a hydraulic,actuator using pressure established by a pump on the vehicle or other equipment carrying the battery cassette handler, and that pump can conveniently be driven by an electric motor energised from the batteries in the cassette through a flexible lead before the cassette has been lifted into position.
The handler is conveniently used in combination with a battery cassette which has readily detachable wheels or castors on which the cassette can be manhandled to a position underneath the vehicle. Then
after the cassette has been lifted into position and the pins are engaged in the brackets, the castors can be released and stored in the vehicle.
The cassette will usually comprise a frame having fixings capable of ready engagement with the brackets by the engagement means, and also having fittings for simple engagement with and disengagement from the cassette engagement means on the ends of the cables. Thus, the cassette engagement means are engaged with the fittings, and then the actuator is operated to lift the cassette; then the pins are engaged between the handier brackets and the cassette fixtures; then the actuator is released and finally the cassette engagement means are disengaged from the fittings.
In a preferred embodiment of the invention, each of the cassette fixtures includes a stop which can act to define the limiting lifting position of the battery cassette, and by virtue of a conical lead-in portion can guide the cassette into the correct position in the handler, and by virtue of a spring loading can then provide some transverse load on the engagement pins to keep the cassette securely engaged even when the vehicle is moving over rough ground.
In that preferred embodiment each cassette fixture includes a lever pivctaily connected respectively to the cassette engagement means, to the cassette frame, and to the spring loaded stop to
enable there to be both a lifting action, and a spring loading action for the purposes described above.
Engagement pins can be normally housed in tubes or other guides on the cassette frame, and simply slid into engagement with the brackets when the battery cassette has been lifted.
The invention may be carried into practice in various ways, and one embodiment will now be described by way of example, with reference to the accompanying drawing, in which;
FIGURE 1 is a perspective view of a battery cassette, and of certain components of the cassette handler; and FIGURE 2 is a detailed elevation to an increased scale of one of the four cassette fixtures.
The vehicle itself is not shown, and it is sufficient to say that at two points along each side of the chassis are fixed depending brackets 11 and adjacent each bracket is the fixed end 12 of a sleeve 13 in which a cable 14 can slide, the other ends 15 of the four sleeves being secured side by side to a fitting secured to the vehicle chassis. The end. of each cable 14 carries a cassette engagement boss 16. At the other ends, the cables are connected through to a trunnion compensator 17, which is mounted on a lever 18 arranged zo be rocked by a hydraulic actuator 19 so as tc pull all the cables 14 up through their sleeves 13 or to return them to the projected position shown in FIGURE 1. The actuator
19 is powered by hydraulic fluid pressurised by an electric motor driven pump (not shown) for providing power steering and other services to the vehicle. The motor for driving the pump is energised from the batteries.
The batteries are contained in a large flat case or cassette 21, which has to be readily removable from the vehicle when the batteries are discharged and readily replaced by another cassette containing charged batteries.
The cassette frame includes two fixtures 22 along each side, the positions of the fixtures corresponding with those of the cable sleeve ends 12. One fixture is shown in more detail in FIGURE 2. Each fixture has a pair of upstanding arms 22 arranged to be on either side of the depending chassis bracket 11 as shown in FIGURE 2 in which position the fixture can be supported from the bracket by means of a steel pin 23 which extends through corresponding holes in the arms 22 and the brackets 11.
Pivotally mounted on the fixture at 24 is a lever 25 which is also pivotally mounted at its respective ends to an engagement socket 26 ( not shown in FIGURE 2) and to a guide and stop pin 27, which carries at its upper end a frusto-conical probe 28 which engages a hole in the underside of the bracket 11 to provide correct lateral positioning cf the fixture, and-thereafter acts as a stop when the upper end 29 strikes the underside of the bracket 11, or the chassis on which it is mounted. The probe 28 normally rests on the top
of a conical elastomeric bush 31 seated in a frusto conical ring 32 fixed to the fixture.
When a cassette of recharged batteries is to be fitted to the vehicle, it is wheeled approximately into the correct position under the vehicle on a set of four legs and castors 33 each of which is readily releaseable from the lower end of one of the fixtures 22 by a quick release pin 34.
The sockets 26 are engaged with the bosses 16 on the respective cable ends and an electrical connection from the battery assembly is plugged into a complementary connection on the vehicle, so that the pump can operate to pressurised the vehicle's hydraulic supply, and the actuator 19 can be operated to pull the cables 14 upward along their sleeves 13.
The first movement of the cables causes the lever 25 to pivot in a clockwise direction, as shown in FIGURE 2, about the fulcrum 24, so that the probe 28 starts to compress the elastomeric bush
31, and then when the compressive force in the bush equals the force in the cable, further movement of the cable along its sleeve lifts the complete fixture with the battery cassette 21 so that the probe 28 enters the co-operating hole in the corresponding bracket 11 and is correctly laterally located. Lifting continues until the probe is stopped at 29, and in that position the pin 27 can be slid frcm its tube 35 into all four holes, two on the arms 22, and two on the brackets 11. The pin has an eight of an inch
radial clearance with each hole, so that when the actuator is returned to its original position, the arms 22 drop by a quarter of an inch as the. two clearances each of one eight of an inch, are taken up. The original compression of the bush 31 was due to a half inch movement of the probe 28, so that even when the clearance has been taken up, there is still some compression in the cone which applies a transvere load to the probe and to the chassis which results in a downward transverse force on the pin providing loading in addition to the weight of the battery cassette, and this effectively clamps the pins firmly between the holes and reduces the likelihood of the battery cassette lifting off its mountings during travel over rough roads.
Finally the castors 33 are removed,. and stored in the back of the vehicle leaving the battery cassette securely located and electrically connected.
Although the sleeved cables 14 are used for lifting the cassette into position because this is a simple light and fairly cheap arrangement without imposing excessive loads on the vehicle floor, the load on the sleeved cables is severe and the sleeves may well be splinted over the straight runs to prevent partial collapse . However once the battery cassette has been lifted into position, it is held on the pins, and the sleeves and cables are no longer leaded.
When discharged batteries are to be removed in their cassette, the operation is the reverse of the operation just described.
The arrangement for engaging the pins 34 in their tubes 35 is quite a simple one. There is a long rod 36 which can turn and slide longitudinally in bearings in the arms 22 of both fixtures, and that can rotate in a sleeve at the lower end of each of a pair of cranks, one at the end of each pin 34 so that as the rod 36 is move longitudinally, it can move two pins longitudinally into and out of engagement with the holes in the brackets 11, and the fixtures 22. There is a slot in the underneath side of each tube 35 to permit the crank to slide. The rod 36 can be secured in either of its extreme positions by means of a pair of stops (not shown) capable of engaging one on one side, and one on the other side of a block 38 mounted on the frame. The rod 36 has to be turned by a 'T' handle 39 to release it from the block, and then it can be slid longitudinally, and twisted to re-engage it on the other side of the block. Replacement of a battery cassette can be effected easily by one man without needing any additional equipment.