US2207297A - Safety device for kick presses - Google Patents

Description

July 9, 1940. J. w. LYNCH SAFETY DEVICE FOR KICK PRESSES Filed Aug. 4, 1937 Patented July 9, 1940.

PTENT OFFICE SAFETY DEVICE FOR KICK PRESSES John W. Lynch, Chicago, llll., assignor to Chicago Flexible Shaft Compa y, Chicago, 111., a corporation of Illinois Application August 4, 1937, Serial No. 157,353

'3 Claims.

This invention relates to safety devices, and has special reference to a safety device particularly adapted for use on kick presses and analogous hand fed devices.

' A large number of accidents in maufacturing plants are occasioned by carelessness or unfamiliarity of the operators of presses andthe like, and considerable difficulty in this connection'is experienced in assembly departments and similar places where small jobs are performed, such as small riveting and similar jobs which are commonly accomplished by manually operated devices such as kick presses. In the case of the latter machines, the operators will frequently kick the lever, bringing the plunger down Without first removing their fingers from beneath the plunger. Various devices have been used on the presses, but'so far as I know, none of them have been successful in completely eliminating accidents of this character. For example, some of these devices have operated satisfactorily when .the

press is allowed to go through its normal complete operation, but when the operator deviated somewhat from the normal succession of events, then frequently the safety device failed to grant complete protection.

. The object of the invention is the provision of ous use of both hands for its release and requiring the maintenance of the locking means in the released position at all points in the plunger stroke toward its engaged position.

Other objects will be apparent from the fol-,

lowing description and the accompanying drawing, in which Figure 1 is a side view of a conventional kick press showing the manner in which the safety device is applied;

Fig. 2 is a fragmentary front view of the press showing the safety device applied thereto;

Fig. 3 is a section on the line 3--3 of Fig. 2, and

Fig. 4 is a view on the line 44 of Fig. 2.

For the purpose of illustrating the invention I have shown the same in connection with a conventional form of kick press which per se forms pedal 1 for rotation of the same about a pivot point 8. The frame 5 carries a slide or plunger 9 reciprocated' by ahead II in response to movement of the treadle 6, the lower end of the plunger carrying a die punch- [2. A die shoe I3 is positioned on the frame 5 opposite the punch 12, and is adapted to be engaged thereby at the lowermost point in the stroke of the plunger 9 to perform the desired work. The upper end of the plunger 9 has a rod It carrying the usual limit stop l5 adapted to engage a projecting portion it of the frame 5 to limit the movement of the punch toward the die.

The safety device includes a. plate I! attached to the plunger 9 by means of cap screws i8 and it and spaced therefrom by means of spacers 2i and 22, the plate being positioned on the forward side of the plunger 9. Dowels 23 and 24 serve to retain the parts in position. Ratchet teeth are positioned on opposite edges of the plate H as shown at 25 and 2%, the two rows of teeth extending therealong a distance slightly greater than the throw or stroke of the plunger 9. Attached to the frame 5 on opposite sides of the plunger 9 are handles 21 and 28 projecting laterally outward, as best shown in Fig. 2, the handles being articulated on bolts 29 and 3! and spaced from the face of the frame 5 by spacing blocks 32 and 33. The bolts 29 and iii are interconnected by a strap 34 retained in position by nuts 35 and :26, intermediate the ends of the bolts 29 and 3|. The handles 2! and 28 are movable between the full line and dotted line positions shown in Fig. 2, and on their inner ends carry detents 31 and 38 positioned to engage the ratchet teeth 25 and 26, respectively, of the plate 11. The detents have pins 39 and 4! extending from the front sides thereof interconnected by a spring 42 tensioned to normally pull the detents into engagement with the ratchet teeth. The plate ll, ratchet teeth. 25 and 26, and the detents 31 and 38, and spring 42 are enclosed within a cover 43 attached to the frame 5 through the bolts 29 and 3|, nuts 44 and 45 serving to retain the cover against the frame.

It will be seen that the handles 21 and 28 are so spaced as to require separate hands for their actuation in order to release the detents 31 and 38 from the ratchet'teeth. Thus, in operation, the work is placedon the dieshoe l3 by the operator, but the pedal 1 cannot be pushed forward in order to move the plunger 9 to its lower tents 31 and 38.

or operative position until the handles 21 and 28 have been moved to their dotted line position shown in Fig. 2. In order for the operator to move the plunger to the operative positions it is necessary that the handles 21 and 28 be grasped in the two hands and pulled to the dotted line position, under which circumstances it is impossible for the hand to be caught between the die punch and the die. However, when the plunger has reached its operative position the plunger can return to its uppermost position after the handles have been released because of the ratchet arrangement of the teeth 25 and 26 and the de- In operation, frequently the operator will not go through with the entire operation but may stop the pedal a part of the way back in the swing, but if at this point either hand is removed from the handles 21 and 28, the plunger is immediately locked at, any point in its swing against further engagement movement until the hand is replaced on the handle. It will be observed that the handles 21 and 28 must be held in the lowermost position during the entire engaging movement of the plunger, and

if at any time during such movement, either hand is removed, the spring 42 will cause one of the detents to be drawn into the ratchet teeth and the downward movement of the plunger to be stopped.

The above description and the accompanying drawing are believed to convey a full disclosure of the invention in conformity with the patent laws.

I claim:

1. A safety device for kick presses of the type having a plunger comprising a plate attached to the plunger, movable therewith and secured against longitudinal movement with respect thereto, said plate having spaced rows of ratchet teeth thereon extending through the amplitude of the plunger stroke, spaced handles rotatably supported on a stationary part of the press for rotation between engaged and disengaged positions, spring means for normally holding the handles in the engaged positions, and detents on said handles adapted to engage said teeth in the engaged position of the handles and to disengage the teeth when the handles are moved to the disengaged position against the tension of the spring, said handles being mounted tomove in a plane parallel with the front of the press and being spaced at such distance as to require both hands of the operator for their simultaneous actuation to hold said detents out of engagement to permit movement of said plunger to the operative position, whereby movement of the plunger toward said operative position will be stopped upon removal of either hand from the handles.

2. A safety device for kick presses of the type having a movable plunger element and a stationary supporting element therefor comprising at least one row of teeth attached to one of said elements and extending longitudinally of said plunger, detents attached to the other of said elements arranged to engage the teeth at any point in the stroke of the plunger to thereby prevent longitudinal movement of the plunger toward its operative position and to ratchet thereon in return movement of the plunger, spring means for normally maintaining said detents in engagement, and a pair of handles for selectively moving said detents out of engagement with said teeth, said handles being mounted to swing in a vertical plane parallel with the face of the press and being spaced apart a distance such as to require both hands of the operator for their actuation to efiect downward movement of the plunger and whereby to stop movement of the plunger toward its operative position upon the removal of either hand from the handles.

3. A safety device for presses and the like having a stationary support and a plunger element movable vertically thereon in a stroke between a normal at-rest position and a finished operative position, vertical rows of teeth on the plunger element, and a hand lever on the stationary support adjacent to each row of teeth and having a detent arranged to engage the teeth at any point in the stroke of the plunger to thereby prevent longitudinal movement of the plunger at any point in its stroke toward its said operative position and to ratchet on said teeth in return movement of the plunger, said detents being constantly urged into engagement with said teeth and adapted to be withdrawn only when ratcheting and upon downward manual operation of the handles, said handles being arranged for operation only in a plane parallel with the front of the press, whereby to necessitate the use of both hands of the operator in the downward movement of said handles in said plane to withdraw said detents and permit operation of the plunger element in a downward stroke, and whereby to stop movement of the plunger element toward its said operative position upon the removal of either hand from the handles.

JOHN W. LYNCH.

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