How to build an electric cab, with detail drawings.
Scale 1/2 inch to the foot.
The working drawings, Fig. 266, are those of a cab suitable for summer use, and are especially intended to illustrate the design of the side elevation, together with the position of the different mechanical features which belong more particularh to an electric motor carriage. The design is a combined illustration in four parts; the central figure (i) is an elevation of the complete cab; the left side (Fig. 2) is a half elevation, front view; the right side (Fig. 3) is a half elevation , rear view; the under side (Fig. 4) is a half plan view; at the top (Fig. 5) is the plan of the sector gears of the steering bar and their movement. To provide for these new designs it was necessary to cut loose from the prevailing idea of the arrangement of this class of motor-electric, and proceed by another path to bring the work up to that standard of high-class carriage building which the vehicle as a mode of travel deserves, and to make it a pleasure carriage, rather than a machine or engine. The effect of beautyjs the predominating force which influences the carriage maker; that other factor, strength, will in the meantime assert itself.
The length of the cab is 9 feet 4 inches; the height is 7 feet; the width, 5 feet 4 inches. The body is mounted on iron curved frames bolted to the four elliptic springs
and to the rocker of the body. The rockers are reinforced with an iron edge plate, screwed to the inside surface from the dash to the lazy back, 2A inches wide and 1/2 inch thick, as shown by the straight line, T (Fig. 2), of the front views of the design (Fig 1). The iron pumphandle-shaped side bars are provided with solid forged flaps, which rest on each elliptic, and are secured by $-inch bolts. The front end of the battery caisson, Z, is supported by iron loops forged onto the pumphandle bars, which pass under the rockers and floor, and are secured by by T bolts to the rocker. A bar of ash is let into the bottom , which in turn holds up the floor that the cells rest upon . This is the front bar of the three which compose the support for the floor of the battery trays, which are made of hard ash, and must be seasoned (kiln-dried). The top of the battery chest is made of dry birch, the grain of the wood running lengthwise of the box, composed of three pieces screwed onto the framing and covered with a paste of white lead and varnish, glue not being suitable for the fixing of the boards. The battery caisson is not fixed to the body; the space separating them is utilized for the passage of the steering and brake rods used in guiding and stopping the carriage. Upon the back end of the chest is mounted a driver's seat on iron braces, G and N (Fig. 1). The seat frame is provided with two compartments; on the near side is the controller, O; on the off side a box provides for a kit of tools, the controller taking up the space of i8 xy x 5 inches.
The handle bar, X (Fig. 1) and X (Fig. 3), operates machinery for starting, stopping and regulating the speed of the motor, A (Figs. 1, 3 and 4). By this means the electric cur. rent generated from the batteries, Z, is controlled bv wires which connect the controller with the motor. The motor shaft is operated upon the driving wheel, Y, with a 2-inch cog meshing into a 14-inch toothed cog,1/2, clipped to the spokes of the driving wheel, Y. The motor is fixed to the 2-inch rear axle by means of the perch plates, R (Fig. 1). The bottom plate forms the clip yoke, which receives the threaded stem formed on the top perch plate, shown by the letters P/'(Figs. 3 and 4). The inside nut is threaded to a 7/16 inch bolt. These plates hold the motor to the axle in rings. The other ends of the perch plates are likewise coupled to the front axle. The perch is made of hickory, the ends of which butt the axle at the front and the motor at the rear.
The top plate of the perch is bridged to receive the steering bar, V, which is pivoted to the arm, W, at d (Fig. 4), and to the fork brace, L, at C. The movement is crosswise from d to d', of the outside knuckle, and from c e of the inside knuckle joint. This distance is io^ inches, this being necessary in order to obtain an angle to the rim of the front wheel, b, of 45 degrees, from b to c' along the dotted line, W(Fig. 4). When the handle bar, B, of the steering gear (Fig. 1) is moved aside 7 inches from the center, E (Fig. 5), to C, the bar, L, by means of the segments, A A (Fig. 5), will move to the point of the pivot, g (Fig. 4). When this handle bar, B, is moved to the right the carriage will be turned to the left side, which result is expected by the driver, as all turns are made to the near side when the driver has the right of way. If we bridge the perch at R (Fig. 1) we increase the rigid support of the motor to the axle. The perch is stronger than it would be if the plate was an unbroken line.
Our drawings are to a scale, and the mechanic can follow the idea, the size of the wheels, springs, and axles can be measured, and so far as the position of the motor, the battery, the controller, the steering gear and brake are conadvantage in favor of this design, and the suggestion is offered that for park and seaside resorts the design is an appropriate one. The line, M (Fig. i), is the slope which the top of the box has that covers up the cogs and rods connected with the brake and steering gear, but left exposed on the drawing to enable us to show the construction of the pivots, the rods and the connections.
H is a bar that braces the perches crosswise; it may be bolted to the plates or welded on; the latter occasions the most work, but has by far the best appearance, and for this, if for no other reason, it should be welded, and if we resort to smooth forgings all the way through, the appearance of the finished carriage will repay the extra expense. To leave the ends of the bars, either wood or iron, unfinished will prove in the end more expensive than to round or chamfer them, or to finish with scroll finish in regular carriage form. This last is the best that can be devised, and then the painter can stripe them and the appearance cannot be adversely criticised. The clumsy appearance of the motor carriages has done much to injure them. If carefully designed at the outset, they can be made to look light and graceful, no matter how heavy the whole carriage may be.
If we take, for instance, the spring bar over the hind spring and cut a scroll on the end to project over the spring, as shown in Figs, i and 3, and let the flap of the pumphandle side bar extend out upon it, with the edges of the iron rounded off, we will have a good looking piece of work. We must secure the top, or the back end of the wing to the body, or to some other support in that vicinity, and the shortest distance to the point of fixture is generally the one selected for this purpose. We fix the stay of the wing to the brace H', and bolt this to the pumphandle side bar and the body, and solid to this brace H. We turn off the stay to take the bottom of the wing, which is bolted. The bolts are first put in through the square hole in the iron of the wing and driven in so as to make a tight fit, the head being countersunk so as not to show on the top of the leather when filed up in good shape. It makes a good job, and one that is not expensive. The work will look as though it was intended to be so, but, on the other hand, if we put the matter off until the job is ironed, and as a last thing begin to calculate where and how to fasten it on, then the trouble and expense will begin and a nice piece of iron work will be spoiled, because of the bolt being just where it can be seen. These small things look well; they are noticeable more than the axles, and they can be turned to add much to the appearance of the work. The point to keep in sight is to work in the regular carriage making way, or better, but not worse.
If there is a machinist who can iron off a motor carriage better than the carriage smith irons off his victoria or brougham, then he can iron anything from a locomotive to a sulky, and this includes all that is heavy or light. The foregoing remarks on the iron and wood work of the motor carriage are suggested by what we have seen, and they are intended to improve the construction of the carriages in this country. They are already strong enough, they are already heavy enough, and they are big enough, but the work is crudely done. It is rough, it is not symmetrical , the irons do not taper, are not correctly swaged, the offsets are not carefully executed, and the setting of the axles is contrary to those rules long established for the construction of the dished wheel and tapered arm. If we dish the wheel we must plumb the spoke, and if we plumb the spoke we must taper the spindle. We cannot do one without doing the other two, for if we desire to avoid the friction of the box and axle we must have the spindle parallel to the ground, and if the spindle is not horizontally set, then the box will crowd either the nut or collar. If we do not dish the wheel it will not stand up for its expected time. The wheels look better when flared out at the top, as shown on the drawings. There is no mechanical problem in the fact that the wheels are driven by a cog wheel that is clipped to the spokes, as in casting this toothed wheel the angle which the flare of the wheel creates can be made upon the pattern.
Any mechanic will admit it is of no consequence what this angle may be. The teeth of the cog wheel, J, can be set to the flare of the wheel, called in the carriage shop the swing of the wheel, and mesh with the one fixed to the shaft of the motor. This will be done as time is given to the work. We know that the front and hind wheels are set to a vertical instead of an inclined plane, and the result is that the wheels appear to lean in at the top, and if set to a vertical line the weight which they carry will spring a 2^-inch axle, so that the axle will off at the top of the collar and on at the bottom of the point of the spindle. These are the facts, and the best mechanic in America cannot change them. Every carnage maker knows this to be true, and this applies to any wheel that has a tapered spindle. It is impossible to taper a spindle and then use a straight or vertical rim, and prevent the above trouble.
We are indebted to the courtesy of "The Hub" for this design and description.