US1295827A - Safety device for punch-presses. - Google Patents

Description

N. MURPHY.

SAFETY DEVICE FOR PUNCH PRESSES.

. APPLICATION FILED NOV- 5. 1912.

1,295,827. Patented Feb. 25, 1919.

QWTEEJD ATES: rarnnr orrren NELSON MURPHY, or DETROIT, MICHIGAN, ASSIGNOR or oNE-To UnTn ToTHoMAs L.

l BUTTON, or DETROIT, MICHIGAN.

Specification of Letters-Patent.

Patented'Feb. 25, 1919.

Application filed November 5, 1917. Serial No. 200,279.

To 'allwho'm'z't may'conoern:

Be it known that I, NELSON MURPHY, a

citizenof the United States of America, residing at Detroit in the county of Wayne and State of "Michigan, have invented certain new and useful Improvements in Safety Devices for Punch-Presses, of which the following is a specification, reference being had therein tothe accompanying drawings.

This invention relates to a safety device for punch presses, and such machines that have predetermined operations when set in motion, the operations being more or less automatic and to a degree beyond the control of the operator of the machine after the machine hasbeen started. 7

The primary. obj ect of my invention is to provide an automaticllocking device adapted to predetermine the operation ofa punch press, when the device is actuated, said device confining the punch press to a single operation, and in this'manner pre'venting a multiplicity of operations, due to carelessness on the part of the operator, breaking; a

part' of; the machinery, or other causes yon'd the control of the operator, which repeated operations may cause an operators fingers to be severed or the operator otherwise injured.

A further object ofi this invention isto provide a Simple, durable and inexpensive locking device for the driven shaftflof a punch press, so that said shaftcan only make one revolution and thereby lower and raise, as a single operation, a punch die or other'tool used in the-machinei My invention will be hereinafter specifi cally described and then claimed, and reference will now be had to the drawing, wherein- Figure 1 is a side elevation of a punch press provided with a safety device;

Fig. 2 is an enlarged longitudinal sectional view of a portion of the machine, showing the locking device for the main shaft thereof; 1

Fig. 3 is a cross sectional view of the looking device;

Fig. 4 is a vertical sectional view of the trip mechanism, and

Fig. 5 is a horizontal sectional View taken on the line VV of Fig. 4.

In the drawing. there is illustrated, by the way of a suitable machine to which the safety device may be applied, a: punch press- 1 having a reciprocable member 2 operated through the medium of a main shaft 3.

This maih'shaft has a'large loose gearwheel' 4 adapted to be driven by a small gear wheel 5 on a suitahl epower, shaft 6. A conventional form 'of clutch 7 controls the operation of the main shaft 3 bythe large gear wheel. 4, said clutch being .spring" pressed and having azpin' 8 extending into a cam groove 9 in'the periphery of the clutch 7. A mechanisnnincluding a pin rock arm 10, a reach rod 11, and a fulcrumed treadle 12 ordinarily control the operation of the clutch 7. "For instance, and as'shown, the clutch 7 is now out of engagement with the large gear wheel 4 and the punch press is inactive." 'When the treadle 12 is depressed, the pin 8 is: removed from the groove 9 and the spring of the clutch forces the clutch into engagement with the hub portion of tl1e l-arge-gearwvheel 4 and establishes a driving relation between said large gear wheel and the main shaft 3;

groove 9 and after one revolution of'the main shaft 3 theclutch 7 is automatically withdrawn or restored to normal position.

Sometimes the operator forgets to remove his foot'from the treadle '12 and at other times' the clutch mechanism breaks and in either instance there are repeated operations of the'pr'ess'which are not only liable to injure the piece'of work lbeing performed clockwise movement or rotation of the main shaft 3. The locking arm 16 has the upper end thereof or an extension 17 thereof connected by a coiled retractile spring 18 to an upright or post 19 carried by the block 14, said spring holding the locking arm 16 normally in engagement with the main shaft 3, so as to sna into the notch 13 when said notch reaches the end of the locking arm 16.

When the treadle 12 isreleased, the pin 8 enters the A suitable casing or housing 20 may inclose that portion of the main shaft 3 in press and then extends upwardly and is connected to a trip member 24 in a casing 25 connected to the side of a punch press. The trip member 24 within the casing 25 has a spring pressed dog 26 adapted for engagement with a dog'27 at the side of a reciprocable member 28 slidable in the casing 25. The dog 27 has a side pin 29 extending into an angularly disposed slot 30 in the'side wall of the casing, and one end of the dog is pressed by a spring 31. Both of the dogs are beveled and at predetermined times are adapted to recede. I

Connected to the lower end of the reciprocable member 28 is a reach rod 32 and said rod is pivotally connected to the treadle 12 to be actuated in synchronism therewith.

In operation and when the treadle 12 is depressed, the member 28 is raised and as the dog 27 engages under the dog 26 the trip member 24 will be elevated thereby shifting the locking arm 16 so as to release the main shaft 3. This operation takes place slightly in advance of the clutch 7 establishing a driving relation between the large gear wheel 4 and the main shaft 3, and in consequence of these. successive operations, the punch press is placed in operation.

As the dog 27 elevates the dog. 26, the former gradually recedes by virtue of its pin and slot connection with the casing 25. Eventually the dog 26 is released and by reason of the first operation the dog 27 is now above the dog 26, and the spring 18 holds the locking arm 16 against the rotating main shaft 3 so as to snap into thenotch 13 when said notch reaches the end of the arm 16. This will take place even though the operator should retain his foot upon the low the dog 27 to assume its normal osition 7 beneath the same. 7

It is thought that the operation and utility of the safety device will be apparent without further description, and while in the drawing there is illustrated a preferred embodi- .ment of my invention, it is to be understood that the structural elements are susceptible to such changes as fall within the scope of the appended claim.

What I claim is The combination with a punch press hav ing a main shaft, and a clutch adapted to automatically control the operation of said shaft, of a pivoted locking arm engaging in said shaft to hold said shaft against rotation, a tri member connected to said locking arm,

a reciprocable member confronting said! trip member actuated in synchronism with said clutch, and a' pivoted spring pressed dog carried by each member with said dogs normally engaging eachother and adapted .to cause said trip me'mber to be elevated by said reciprocable member to withdraw said arm from within said shaft to release the same, and one ofsaid dogs receding over the other when said reciprocable member assumes normal position.

In witness whereof I aflix my signature in the presence of two witnesses.

NELSON MURPHY. Witnesses; V

KARL H. BUTLER, ANNA M. Donn.

Copies of this patent may be obtained for five cents each, by addressing the "Commissioner of Patents, Washington, D. C.

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