US3802820A

US3802820A - Control device for brick press

Info

Publication number: US3802820A
Application number: US00295574A
Authority: US
Inventors: S Iwasaki
Original assignee: Mitsuishi Fukai Tekkosho KK
Current assignee: Mitsuishi Fukai Tekkosho KK
Priority date: 1972-10-06
Filing date: 1972-10-06
Publication date: 1974-04-09
Anticipated expiration: 1991-04-09

Abstract

A control device for controlling the stroke of a brick press. A sliding cam plate is mounted on the block of the press which moves up and down to carry out the compaction of the brick material in the mold, and the cam plate contacts a rotatable friction roller which has an arm thereon with switch contacts at different distances from the axis of rotation of the roller. Switches which are connected into the control circuit of the press to control up and down movement of the block are placed in the paths of the switch contacts and at different angles to the start position of the arm. When one switch is connected into the control circuit, the press will be reversed after one length of pressing stroke, and when the other switch is connected into the control circuit, the press will be reversed after a different length of pressing stroke.

Description

United States Patent [191 Iwasaki Apr. 9, 1974 CONTROL DEVICE FOR BRICK PRESS [73] Assignee: Mitsuishi Fukai Tekkosho Ltd.,

Wake-gun, Okayama Prefecture, Japan 221 Filed: Oct. 6, 1972 [21] Appl. No.: 295,574

Primary E.\'aminerRobert D. Baldwin Attorney, Agent, or Firm-Wenderoth, Lind & Ponack 57 ABSTRACT A control device for controlling the stroke of a brick press. A sliding cam plate is mounted on the block of the press which moves up and down to carry out the compaction of the brick material in the mold, and the cam plate contacts a rotatable friction roller which has an arm thereon with switch contacts at different distances from the axis of rotation of the roller. Switches which are connected into the control circuit of the press to control up and down movement of the block are placed in the .paths of the switch contacts and at different angles to the start position of the arm. When one switch is connected into the control circuit, the press will be reversed after one length of pressing stroke, and when the other switch is connected into the control circuit, the press will be reversed after a different length of pressing stroke.

2 Claims, 2 Drawing Figures CONTROL DEVICE FOR BRICK PRESS Brick presses commonly use a piston which fits in a mold having the same dimensions and presses the material in the mold. In the last part of the downward or compression stroke of the piston, repeated short strokes are used several times to distribute the pressure on the material in the mold equally and also to eliminate air bubbles in the material in the mold, so that the quality of the product is greatly improved.

In this kind of operation the best technique is to end some finishing strokes earlier and others later with good timing. However, such repeating of strokes of the piston has heretofore been controlled manually by the operators handle, and therefore the conventional brick-press inevitably necessitates a highly skilled operator. This lowers the efficiency and increases the production costs.

As is well known, in the most common type of brick press, i.e. the friction press, there are a pair of friction wheels keyed to opposite ends of an electrically driven horizontal shaft and an intermediate wheel is positioned between the two friction wheels. The horizontal shaft is movable axially and the intermediate wheel, by coming in touch with either friction wheel, rotates in one direction or the other, and thereby drives the block and piston up and down by means of a threaded shaft connected to the intermediate wheel.

The axial movement of the horizontal shaft is generally accomplished by some kind of servo motor, which is controlled so as to end the down stroke of the piston, and the pressing of the material in the mold, earlier or later. The servo motor has been controlled by hand directly by the operator.

It is an object of the present invention to remedy such difficulties by fully automating all the press operation. This is achieved by a control device in which the piston movement relative to a fixed point near the end of the compression stroke is so amplified that it makes the handle operation very easy and the fine movements correspond with the movement of the piston.

An example of the present invention will be described in detail with reference to the attached drawings in which:

FIG. 1 is an elevational view,partly in section, of an embodiment of the control device of this invention; and

FIG. 2 is a plan view, also partly in section, of the device of FIG. 1.

In FIGS. 1 and 2, a reciprocating block 1 of the brick press moves up and down with the piston P of the press as it acts on material B in the mold means M. The block is driven by a conventional intermediate wheel and threaded shaft as described above. A bracket 2 is fixed to the block which has laterally opening U-shaped channel 2a therein. The top and bottom edges 3 of a plate cam 6 run in channel 2a. The edges 3 of the cam 6 are loosely connected to the block 1 through bracket 2 by the combination of a pair of fixed pins 4a on the bracket 2 and horizontal slots 4b in the plate cam. Springs 5 are provided between the plate cam 6 and the bracket 2 and press the plate cam horizontally outwardly against a roller 9.

Another fixed frame separate from the brick press has a bearing 8 on which the roller 9 is rotatably mounted. The roller 9 has a rubber ring on the periphery thereof which is contacted by the plate cam 6 under the force of the springs S. The roller 9 has an arm 10 fixed thereto, and two

contact pieces

11 and 12 are adjustably mounted thereon. Two

switches

13 and 14 are mounted on the frame 7 in the respective paths of movement of the contact pieces as the arm moves when roller 9 rotates.

Switches

13 and 14 can be selectively connected so that when contacted by a contact piece the selected switch will close a control circuit (not shown) to end the downward finishing stroke of the press and switch the operation of the apparatus to an upward stroke, and when the contact piece is separated from the switch, the apparatus is switched to the downward stroke again. The contact piece 11 and switch 13 are at radius a and at angle 0,, while contact piece 12 and switch 14 are at radius (a+b) and angle 0 Since the angle 6, is larger than 0 the time from the start of movement of the arm 10 to the time of contact of the contact piece 11 with the switch 13 will be greater than the time to the contact of the contact piece 12 with the switch 14. This means that when the switch 14 is connected into the the control circuit, the downward stroke of the piston P will end earlier than when the switch 13 is connected into the control circuit.

The operation of the device is as follows. When the block 1 is driven by the intermediate wheel and screw so as to descend, the piston P squeezes the material in the mold, and the cam plate 6, being urged outwardly by the springs 5, drives the roller 9 and the arm 10 in the direction of the arrow. When switch 14 is connected into the control circuit, the downward stroke of the block 1 will be relatively short, and the stroke will be repeated relatively rapidly, whereas when the switch 13 is connected into the control circuit, the downward stroke will be relatively long and the stroke will be repeated somewhat more slowly.

By appropriately switching the switch 13 and switch 14 into and out of the control circuit for the press, the press can be caused to carry out automatically short relatively quick strokes for a part of the pressing operation, and then by changing the connection of the switches to the control circuit, the press can be caused to carry out automatically long heavy strokes. By simple electrical means, and the use of a conventional program means, the switchover can be accomplished automatically according to a program for the particular articles being molded. The need for a skilled operator'to control the press manually is therefore eliminated.

I claim:

1. A control device for a brick press having a block which moves up and down for pressing the brick material into a mold, said device comprising a bracket adapted to be attached to said block, a cam plate slidably mounted for horizontal movement in said bracket, spring means engaged with said cam plate urging said cam plate horizontally, a roller having a rubber ring therearound and mounted for rotation at a fixed point adjacent said bracket and engaged by said cam plate for rotating said roller as said block moves up and down, an arm on said roller, at least two contact pieces mounted on said arm at different radii from the axis of rotation of said roller, and a switch mounted in the path of movement of each contact piece as the arm moves during rotation of the roller, said switches being at different angles to the initial position of said arm, and said switches being adapted to be selectively connected to the control for the drive for said brick press.

2. A control device as claimed in claim 1 in which said contact pieces are adjustably mounted on said arm.