US2887895A - Torque motor booster for clamp treadle of paper cutters - Google Patents

Description

C. THUMIM May 26, 1959 2,887,895 MOTOR BOOSTER FOR CLAMP TREADLE OF PAPER CUTTERS Filed March 26, 1956 TORQUE 5 Sheets-Sheet l o 000 o o .M M: NU T mm r m g m C- THUMIM May 26, 1959 TORQUE MOTOR BOOSTER FOR CLAMP TREADLE OF PAPER CUTTERS Filed March 26, 1956 3 Sheets-Sheet 2 INVENTOR.

C. THUMIM TORQUE MOTOR BOOSTER FOR CLAMP TREADLE OF PAPER CUTTERS Filed March 26, 1956 3 Sheets-Sheet :5

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United States Patent TORQUE MOTOR BOOSTER FOR CLAMP TREADLE OF PAPER CUTTERS Carl Thumim, Westbury, N .Y., assignor to E. P. Lawson Co., Inc., New York, N.Y., a corporation of New York Application March 26, 1956, Serial No. 573,942 Claims. (Cl. 74-388) This invention relates to guillotine type paper cutters and more particularly to the clamp actuating means thereof.

The purpose of this invention is to provide means for augmenting the manual effort required for pressing a clamp-operating foot pedal of a paper cutter. Thus, in paper cutters having manually operable cutters, wherein an operator has to step on the treadle to actuate the clamp, considerable force is needed. Such force may vary from 40 pounds at the beginning of a stroke to about 140 pounds at the end of a stroke. Needless to say, repetitious effort of this kind becomes exceedingly tiring. Accordingly, the invention provides power operated means for effecting most of the required force. The effort exerted by the operator is in an amount to supply the difference between the actual clamping force required and the force effected by the force boosting device disclosed herein. Such ditference in force which must be provided by the operator can be held to a minimum limit so as to normally preclude a tiring effect.

The invention can be used in conjunction with automatic clamp actuating mechanisms for purposes of manually gauging a out, since disturbance of the paper pile by the relatively slow action of my manual arrangement with power booster is kept to a minimum.

Briefly, the invention comprises the use of an electric motor of a type which can remain non-rotative even while current is going therethrough, without burn-out, the motor shaft, however, exerting a torque which may be mechanically coupled to the clamp through the same linkage as is actuated by the foot treadle. Such motor torque thus augments the foot treadle force and may, of course, be considerably in excess thereof. The arrangement is such that the motor is automatically energized when the foot treadle is initially pressed.

Other objects and features will be apparent from the detailed description of the invention which now follows in conjunction with the appended drawing in which:

Figure 1 is a front View of a guillotine type paper cut ter showing the general arrangement of certain elements which make up the novel combination.

Figure 2 is an amplified view of a portion of Figure 1 showing details of the elements.

Figure 3 is an amplified drawing of the motor switch actuating device.

Figure 4 is a fragmentary elevation showing the arrangement of the motor and certain elements driven thereby.

Figure 5 is a forward view showing the motor driving arrangement.

Figure 6 is a fragmentary drawing of certain details of the combination.

Referring now to the drawing, the invention comprises a paper cutter, as shown, having the usual frame F carrying the knife K behind which is clamp C. The details of the clamp are not shown since it is conventional in character and operated by a conventional arrangement, for

example, as shown generally in Patent No. 2,570,873 owned by the assignee of the present invention. Such arrangement comprises a spring S and other elements heretofore well known. Thus, the spring S biases treadle T through sprocket chain 6 to a position where the clamp is not in use. A dog D is fastened to a rod R which rides in a suitable bearing in the machine framing. The dog D abuts a pin P and transmits force thereto to motivate the clamp in a manner as set forth in the abovementioned patent.

Sprocket chain 6 has one end secured to the dog D and thence passes around an idler sprocket 9. The other end of the chain is secured to the foot treadle T through a yoke 4 having spaced arms 4a and 4b through which a pin 7 passes and which yoke carries a switch to be actuated in a manner to be described.

As shown in Figures 1 and 4, an arm 8 is integral with the foot threadle which may be pivoted at 12 to the machine frame. Any suitable mode of fastening the pin 7 with the arm 8 may be used, the details of which are not essential. The chain 6 terminates in a pin 40 which passes through the top portion 40 of the yoke and has bearing in a spring housing 42 welded to portion 40. Within the spring housing a spring 43 is disposed bearing against a nut 45 threaded on pin 40. The weight of the treadle is thus carried on the spring 43. A small gap 45a exists between the nut 45 and the bottom of the spring housing 42. Thus, it will be apparent that owing to the integral fastening of the yoke with the spring housing 42, if force be applied to the treadle the spring 43 will be compressed because the yoke 4 is initially pulled down, nut 45 being momentarily stationary due to the resistance chain 6 meets via dog D and pin P. The bottom surface of the housing 42 meets the nut 45 to limit the relative motion.

A switch 46 is carried within the yoke 4 having a pin 46a which is released when the yoke moves downwardly to a sufiicient extent to close the lost motion gap between elements 42 and 45. Release of pin 46a serves to close the switch to energize an electric motor 50 carried by the machine frame.

The shaft 50a (Figure 4) of the motor carries a sprocket wheel 54 which is connected by a sprocket chain 56 to a sprocket wheel 57 which drives a shaft 58 carrying a sprocket 60. The sprocket 60 has the end of a single length of chain 64 (Figure 2) fastened thereto at 61, the other end being fastened to an arm 66 which is secured to the sprocket 9 as by bolts 68.

From the above description it will be apparent that if the motor turns clockwise, the chain 64 will efiect a downward pull on arm 66 to exert force on the sprocket chain 6. This causes I e pin P to move to the right for the purpose of lowering the clamp through mechanism described in Patent No. 2,570,873.

When the treadle is released, the spring S pulls the combination comprising chain 6 and yoke 4, etc. back to starting position, at which time the gap between spring housing 42 and nut 45 is once more created, the lower end of pin 40 then serving to push the pin 46a back to open contact position.

A particular feature of the arrangement is that the torque effect of the lever 66 is gradually increased due to the change in moment arm in length from d to D as shown in Figure 2. Thus, as the stroke of the clamp progresses the force on the clamp due to the motor is constantly increasing. This has the advantage of balancing the force needed to overcome the increasing load of the clamp return springs as used in a conventional clamp mechanism.

The particular arrangement is so designed that the motor will supply somewhat less force than is required assaees for full movement of the clamp, the additional force being provided by the operator acting on the treadle. Owing to the fact that the particular type of motor used will not overheat even though energized without rotating for a period of perhaps two minutes, the operator can keep his foot on the treadle for that period at least, being materially assisted by the torque of the motor in maintaining the clamp pressure on the paper pile. While the motor can be designed for continuous energization, it would require a larger motor costing a great deal more.

' From the above it will be apparent that an operator need supply only a small part of the energy required for clamping the paper pile while at the same time having full and immediate control of the clamping action.

I'am aware that various modifications of the basic concept are possible and accordingly do not seek to be limited to the exact arrangement disclosed hereinabove except as set forth in the appended claims.

I claim:

1. In a clamp mechanism for a paper cutting machine, a manually operable treadle, a sprocket wheel, a sprocket chain passing over a portion of said wheel and having one end connected to a clamp actuating device and the other end connected to said treadle; an electric motor, and tensile means connecting said motor to said sprocket wheel so as to efiect a booster torque on said wheel when said motor is energized.

2. In a device as set forth in claim 1, including a torque arm on said sprocket wheel, said tensile means being connected to said torque arm, said torque arm being disposed to efiect increasing torque on said sprocket wheel during the course of rotation.

3. In a clamp mechanism for a paper cutting machine, a manually operable treadle, a sprocket wheel, a sprocket chain passing over a portion of said wheel having one end adapted for connection to a clamp actuating device and the other end connected to said treadle, a switch control means, an electric motor, means connecting said motor for exerting a booster pull on said sprocket chain, said sprocket chain being connected to said treadle through i 4 said switch control means, whereby initial manual pressure on said treadle closes said switch to energize said motor.

4. In a device as set forth in claim 3, said switch control means comprising a housing, a switch carried in said housing, said housing being secured to said treadle, a spring in said housing, said sprocket chain having an element abutting an end of said spring, the other end of said spring abutting a portion of said housing whereby said spring is in initial compression by virtue of the weight of said treadle, said housing having a lost motion connection with said abutting element, a switch carried by said housing actuated by take-up of lost 'rnotion when said housing is initially motivated by manual pressure on said treadle.

5. In a clamp mechanism for a paper cutting machine, a manually operable treadle, actuating means mechanically connected to said treadle for moving a clamp by direct action of said treadle when an operator applies force thereto, and means for augmenting the force applied by said operator on said manually operable treadle comprising an electric motor mechanically coupled to said actuating means, and means for energizing said motor when said manually operable treadle is initially actuated, said actuating means comprising a sprocket wheel, a sprocket chain around a portion of said wheel having an end extending to said clamp actuating means and another end connected to said treadle, an electric motor mechanically coupled to said sprocket wheel, and means for energizing said motor to exert torque on said sprocket wheel upon initial motion of said treadle.

References Cited in the tile of this patent UNITED STATES PATENTS 819,718 Bredenberg May 8, 190.6 1,191,612 Radiguer July 18, 1916 1,409,821 Bremberg Mar. 14, 1922 2,330,569 Esnault-Pelterie Sept. 28, 1943 2,505,555 Levy Apr. 26, 1950

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