US2626030A - Automatic clutch control means for press brakes - Google Patents

Description

Jan. 20, 1953 H. H. GOLDBERG AUTOMATIC CLUTCH CONTROL MEANS FOR PRESS BRAKES Filed Dec. 10, 1951 ISnoentor Fig.5

HARRY H. GOLDBERG ,2 ENE:

Patented Jan. 20, 1953 AUTOMATIC CLUTCH CONTR OILMEAN S FOR' PRESS. BRAKES.

Harry I-I. .Gioldberg, .Denverrflolo.

Application December 10, 1951, @Serial N b.'260',81'6f:

l 2 Claims.

This invention relates to improvementsirr steel press brakes of thetype now extensively employed', and relates more particularlyto an attachment for the automatic'control of the power transmitting clutch.

Press-brakes of the type to which this invention relates have a stationary bed plate,- a ram plate positioned therea'bove, means comprising a cam shaft having camsoperatively connected with the ram plate,- means for turning the camshaft comprisin a "clutch, and pedal" means for'controlling the operation of i the clutch.

In the operation of presses of'this type; the clutch is closed byexerting pressure on a pedal bar and opened whenthe pressure is removed from'the'bar. As'long as-pressure'is applied'to the-bar; the cam shaft continuesto turn and the operator'must therefore watchthe'positionof the ram plate in order to open the clutch at the proper time: The operators attention must therefore be divided betweenthefeeding of the press and the control of the clutch to stop the ram plat'e 'at the-proper place.

It is the object of this invention to provide such presses. with meansthat locks the clutch in operative position when the pedal bar is depressed-to close the clutch and which automatically releases thelatchand-opens the clutch when the. ram plate "has" returned to a predetermined position atthe endsof-its-cycle.

A" further obj ect-"is' 'to' provide an attachment or-means that will-make it unnecessary for the operator to keep one foot in constant engagement with the pedal bar and limits such engagement to a single application of force at the beginning of each cycle.

The above and other objects of this invention which may appear as the description proceeds are attained by means of a construction and an arrangement of parts which will now be described in detail, for which purpose reference will be had to the accompanying drawing in which Figure 1 is a perspective view of a well known steel press brake showing the same as it is now marketed, the attachment being indicated in position thereon.

Figure 2 is a side elevation, looking towards the left in Fig. 1, and shows the attachment, which forms the subject of this application, in place thereon;

Figure 3 is a view partly in section and partly in elevation, taken on line 33 Fig. 2, showing the attachment to an enlarged scale;

Figure 4 is a side elevation looking towards the left in Fig. 3 and 21 Figure" 5* is"a'view similarto that-shownin Fig: 3.

Referring now to the' drawing; reference nu:

I merals R" and IBL designate respectively" the right andthe left sides of the housing; The sides are joined at their tops by a crown section II. The sidesareconnected near their lower-ends by bars l2 and l3 and bed plate I3a. Cam shaft I4 is" mounted for rotation in' bearings [5; two" of which have-been shown; Theshaft carries two eccentrics that are surrounded by straps 16 which are adjustably connected with" ram plate I1. Powerisusually supplied'bya constantly operating electriomotor, which has not been shown; and motion is transmitted to the cam shaft by a clutch (notshown) which is opened and closed by a pedalmechanism comprising the pivoted levers l8'and rod l8a and pedal rod [9.

The press brake shown in'Figs. 1 and 2 is on the market. and its constructionis well known. The above description has been given'merely'for the purpose .of facilitating the descriptionof the attachment and its operation; Referringnow to Figs. 1 and2, it will be seen that the free ends of L'levers l8.areiconnected by a pedal bar. or pedal rod. A spring, which is not visible in Fig. 1 serves to hold. leverlii' in the elevated clutchopen positionshown in. Fig. 2, and for. the purpose of visualelaritya spring S has been shown on the outside and/this represents the hidden spring. When'the parts are in the position shown in Fig. 2; the clutch is open and the ram plate is stationary. When levers I8 are moved to the position shown by dotted lines in Figs. 2 and 5, the clutch is closed, and shaft l4 turns moving the ram plate in a vertical direction. It is customary to stop the shaft with the eccentrics at top dead center and therefore when the cam shaft begins to turn the ram plate starts moving downwardly. In the usual way of operating the press, the operator must keep his foot on pedal rod [9 until the cam shaft has made a complete turn, which becomes very tiresome.

The invention or attachment to which this application is directed consists of a bracket 2| attached to the ram plate and, a latching mechanism attached to side IUR near its lower end. The latching device consists of a steel casting or forging that has a base 22, which is secured to the side by suitable means such as bolts 23. Extending outwardly from the base is an arm 24 that has two spaced lugs 25 between which is mounted for pivotation a bell crank shaped member having an arm 26 which extends in a generally horizontal direction and a pawl 27 that extends vertically. A rod 28 has its lower end pivoted at 29 to the end of arm 26 and extends upwardly through a hole in bracket 2| and terminates above the bracket in a threaded section to which two adjusting nuts 30 are connected, one of which serves as a lock nut. Attached to rod 28, directly below bracket 2|, is an arm 3| that can be moved longitudinally on rod 28 and be clamped in adjusted positions by a set screw 32 or any other suitable means. Attached to side IDR is an anchor loop 33 such as an eye bolt, which forms a stationary anchor for the lower end of spring 34 whose upper end is attached to arm 3 1. Spring 34 is always under tension and therefore tends to move rod 28 downwardly. From Fig. 5 it will be seen that the up and down movement of rod 28 rocks pawl 21 about its pivot. When the ram plate is in its uppermost position, as shown in Fig. 2, pawl 21 is in the full line position which is the position that corresponds to open position of the clutch. When the operator exerts sufficient pressure on pedal bar 19, levers I8 move to the dotted line position shown in Figs. 3 and 5 and closes the clutch, whereupon the cam shaft starts turning and moves the ram plate downwardly. As bracket 2| moves downwardly, spring 34 moves rod 28 downwardly and turns pawl 21 in a counterclockwise direction. When bracket 2| has moved away from nut 30, the pawl is then in the dotted line position shown in Fig. 5 and prevents levers l8 from moving upwardly in response to the force exerted by spring S; the clutch therefore, remains closed until lever 18 is released which occurs when bracket 2| in its upward movement engages nuts 30 and moves bar 28 upwardly to a point where lever I8 is released whereupon spring S immediately moves the parts to the full line position shown in Fig. 5 and opens the clutch. The exact point at which lever I8 is released and the clutch opens is determined by the position of nuts 30 and can therefore be adjusted.

In the event that the automatic clutch release is not wanted, hook 35 which is pivoted at 36 to the upper end of arm 31, is moved into the dotted line position shown in Fig. 5 and holds pawl 21 in inoperative position.

Attention is directed to the fact that presses equipped with the automatic clutch latching and automatic clutch release do not require the operator to exert pressure on the pedal rod continuously during the entire cycle of ram plate movement as is now necessary. With presses provided with the control means above described, the operator exerts a single pressure on the pedal rod, which moves it into latching position; he can then remove his foot from the pedal bar until he initiates the next cycle.

This attachment is simple and can readily be attached to existing presses. If the control means is built into the'machine at the factory, it is obvious that the several elements can be replaced by equivalent elements located differently, but still performing the same function.

What is claimed as new is:

1. The combination with a press brake having its working head cam-engaged with a shaft for reciprocation of a ram plate by rotation of the shaft, a clutch adapted to engage the shaft with driving means, a spring held foot treadle adapted to be depressed in the direction of the working stroke of the ram plate, and clutch shifting means adapted to shift said clutch to the shaft engaging position responsive to the depression of the foot treadle; of a bell crank with one arm forming a hook adapted to latch the foot treadle in its depressed position and the other arm forming a lever movable in the direction of the foot treadle depression to rotate the hook arm into latching position, means to resiliently hold the bell crank in the latching position, a rod connected to the lever arm, a bracket on'the ram plate slidably engaging said rod, and a stop on the rod adapted to be engaged by the bracket at the retracted position of the ram plate and to hold the bell crank in the unlatching position at said retracted position.

2. A device in accordance with claim 1 in which means is provided for holding the bell crank in unlatching position independently of the position of the ram plate.

HARRY H. GOLDBERG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 945,551 Knoell Jan. 4, 1910 1,040,441 Seybold Oct. 8, 1912 1,102,609 Scherer July '7, 1914 2,052,752 Criley Sept. 1, 1936 2,594,909 Georgefi Apr. 29, 1952

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