Details of the T1880 parts

"How can I see at a glance if my machine contains this new mechanism !?"

« Old tens-carry mechanisms. - To fully show the advantage of the new tens-carry mechanism invented by Mr. Thomas de Bojano, compared to the old one, we will first describe the old mechanism, which was subject of the patent expiring in 1880.

Each dial, as we have describe above, carries a steel cam that, if the dial passes from 0 to 9 or from 9 to 0, pushes out horizontally the part that we call tens-carry hook; if that hook is pushed out, it will drop the tens-carry finger, by means of a part called the tens-carry lever or yoke.

This lever rocks on a pin that sticks through it and is mounted in a copper stud that is split to let the lever pass; the stud is mounted on the frame by a screw.

The lever acts on the tens-carry finger by means of a rod which has a groove to receive the yoke of the lever; the rod carries at its end a little steel yoke that enters the circular groove in the base of the controlling drum.

When the round rod moves down, it drops the controlling drum and the tens-carry finger attached to it; if this finger turns, it turns over one tooth the tens-carry wheel mounted on the base of the Geneva wheel. The base of the controlling drum, with its spirally shaped end, meets, during its rotation with its square axle, a steel foot with inclined ends that force the controlling drum and tens-carry finger to return to their original position. The tens-carry finger then passes between the gear and the Geneva wheel, until the dial passes from 0 to 9 or from 9 to 0, depending on the operation, and will push out again the tens-carry hook and drop the finger.

This tens-carry is made reliable by means of double springs, riveted on a support that is mounted by a screw on the round rod carrying the tens-carry yoke.

The above-mentioned springs folded at right angles pass through a frame plate, which is countersunk in two parts with sharp angles, such that, if the tens-carry finger moves up or down, the springs go from one side of the frame plate to the other.  

Let's summarize the parts of the tens-carry mechanism and describe those of the new mechanism :

Old tens-carry mechanism.

1)         Tens-carry hook

2)         Tens-carry lever with block and its foot

3)        Split block for the lever

4)        Pin

5)         Screw

6)         Yoke

7)         Round rod;

8°and 9° Two springs

10)      A support for the springs

11)       A screw

12)       An iron brace with square hole for the large axle 

13)       A steel wedge riveted on the frame 

14)       Geneva wheel 

15)       Its base 

16)       The tens-carry gear 

17)      A controlling drum 

18)      Its base 

19)      A spiral part at the bottom of said base, to let it go up the wedge

20)      A tens-carry finger

New mechanism.

1)         A hook

2)         A Geneva wheel 

3)         Its base

4)        The tens-carry gear

5)         A controlling drum

6)         Its base

7)         A tens-carry finger

8)        A simple spring

9-10)   two screws to fix said spring

Total,  10  parts to perform tens-carry instead of 20.

Each set is repeated seven times in a 12-digit machine; nine times in a 16-digit one, and eleven times in a 20-digit one; or 70 parts instead of 140 in 12-digit machines; 90 instead of 180 in 16-digit ones, and 110 parts instead of 220 in 20-digit ones.

The tens-carry hook b (fig. 2), which is extended by a bent and counter-bent rod, enters the circular groove in the end of the base of the Geneva wheel and acts as a lever.

When the dial passes from 0 to 9 or from 9 to 0, depending on the operation, its cam will push out the tens-carry hook. The lever-like extension of the hook shifts the Geneva wheel, which has a base that can move along a square axle. The Geneva wheel will pass in front of the notch made for the 10th tooth on the controlling drum that is mounted on the axle, as well as the tens-carry finger.

During this movement the tens-carry gear is brought in front of the finger, which will turn it by one tooth to perform the tens-carry.

The extension rod of the tens-carry hook, which is bent and counter-bent, has a shaped end that can enter the circular groove in the base of the Geneva wheel; the cross-section of the count-bent part is ^-shaped and forms two inclined planes which support a simple bent spring, fixed by two screws on the small back plate of the frame. This spring enforces the position of the Geneva wheel, at the top or bottom, depending on the tens-carry being made or not.

When operating the machine, all tens carry levers that are dropped during the turn of the crank, stay down.

To enable the tens carry levers to be used in a new cycle, the crank moves a round steel shaft by means of a release mechanism on returning to its starting point. The shaft passes in front of all Geneva wheels and is equipped with yokes that descend from the shaft between the Geneva wheel and the tens-carry gear.

The release mechanism rocks the round shaft and its yokes, which put all Geneva wheels, that where moved by the tens-carry, back to their original position. »