The open edge of the comb A, when in place, lies immediately behind the jaws, and the bristles are drawn into, and more or less compressed within, each tooth space c in succession, by toothed feeding bars F F, pivoted at g, to a pair of outside horizontal slides G G, which are slotted at h to receive guide pins i, connected with the main frame. The toothed portions of the feeding bars F F lie over the bristles on the jaw D, and are held in a raised position, so as to be clear of them, by means of a spring 1; and a forward traverse motion is given to tl3e slides which carry the feeding bars, by means of a spring H, and cord or chain k.
To feed the bristles into a space c of the comb, power is applied by foot to a treadle below. This pulls upon duplicate curds m, which are connected with dogs I, pivoted on the feeding bars F F, and so arranged in relation to the slides G G and the stops n, that their first action is to draw down the toothed feeding bars F F into the bristles, and afterwards to draw the bars and slides backwards, by which the bars F F are made to distribute and pack, as required, the bristles within a tooth space c of the comb. The foot is then removed from the treadle, and the parts resume their normal position, to effect the filling of a succeeding tooth space, and so on till the comb is full.
The comb A is retained in position and fed or allowed to drop as required, so as to bring each tooth space in succession into the receiving position for the bristles, by means of pawls J K, the former of which, catching in the holes 8 of the comb, simply serves to keep it from dropping too far while the latter is out of contact with the teeth of the comb, it being adjusted to enter suc cessively within the tooth space c, to hold the comb at its precise required height. Towards the close of the back or feeding-stroke of the bars F F, pins on them strike levers, which, bearing against studs P of the pawl K, release the latter from the comb to provide for its next downward feed. When the feeding bars F F and slides G move forward again, a projection connected with them releases the pawl J to admit of the comb completing its drop ; the pawl K being now released from the action of the lever, catches between a succeeding pair of teeth, for repetition of the crowding of another lot of bristles within the next tooth space of the comb, and so on till the filling is complete.
The Woodbury machine uses bristles, hair, tampico, or any other material equally well, and firmly secures the bunches in backs of wood, leather, indiarubber, bone, ivory, or other substances. It works 75 to 80 hunches per minute with the greatest ease, and fills an ordinary scrubbing-brush back in about the same time. Though extensively used in America, this machine has not been received with favour in England, an objection alleged against it being that the wire used for binding the bunch occupies so much of the hole as to prevent the bunch from fitting closely.
Bound Brushes.—Round brushes for cleaning bottles, lamp-gla.sses, and other cylindrical vessels, are made by fastening the bristles, which project both ways, between two wires, which are then firmly twisted together.
Steel Brushes.—For cleaning and removing sand from castings, very durable brushes are made by substituting for the bristles, a series of flat, well-tempered steel wires. They are an American manufacture, and are sold at 5i to 18 dollars (say 23 to 75 shillings) per dozen, a,ecording to size.
Iron-wire Brushes.—Headed pins of ordinary iron wire are fixed in some elastic material, which is then attached to a thin sheet of metal, dished or bent so that the margin can be inserted in the undercut margin of a recess formed in the handle or back, as seen in Fig. 408. When the metal is bedded down upon the back a, the edges of the plate enter the recesses (Figs. 409 and 410), and it may then be secured by screws. If the plate be of steel or other metal having a degree of resilience, it may be sprung into place, and other fastening be dispensed with. The attachment of the elastic material to the plate is effected by sewing or riveting to the previously nicked or perforated plate, or by clamping over the edges of the plate, or by slitting them and turning up parts to be passed through the elaatio material and clamped down. Fig. 411 shows a margin which bas been elided ; either needle and thread or rivets may be passed through. Fig. 412 is an example of clamping ; in Fig. 413, the teeth are pointed for forcing through the material.
By another plan, the elastic material ia fixed on a piece of wood by meana of pins driven through the folded margin of the material and into the wood, or aecured by stitches across the back, or by binding wire, &c., in a groove on the wood. The wood ia then screwed to the handle, or cemented into a recess by shellac. Figs. 414 and 415 allow the attachment by piva. In Fig. 414, the margin ia ao wide that it can be folded over the edge of the wood to the back ; pins c are then driven through, or the opposite margins at c c are sewn together across the back. Fig. 416 shows an oval piece of wood fitted with a groove d on the edge ; the edge of the material ia folded over this, and embraced tightly by a coil of wire. In Fig. 417, the piece of wood is fitted into a recess in the handle or back A which is of papier-mache, vulcanite, or of various moulded compositions. A brush ia shown in Fig. 418 i is a piece of wood to which the material ia secured ; it ia then fixed in a recess formed in the wooden back k, which ia covered with plush, whoae edges are folded underneath, hidden and secured by the back.