US2775009A - Pump mechanism for type casting machines - Google Patents

Description

1956 E. c. MELDRUM ET AL 2,775,009

PUMP MECHANISM FOR TYPE CASTING MACHINES Filed Aug. 14, 1953 4 Sheets-Sheet 1 WQM ZE M A 7' TORNEYS Dec. 1956 E. c. MELDRUM ETAL 2,775,009

PUMP MECHANISM FOR TYPE CASTING MACHINES Filed Aug. 14, 1953 4 Sheets-Sheet 2 4 NM I i By Y W ATTORNEYS.

1956 rc. MELDRUM ET AL 2,775,009

PUMP MECHANISM FOR TYPE CASTING MACHINES Filed Aug. 14, 1953 4 Sheets-Sheet 3 mm P6 9 1956 E. c. MELDRUM ETAL 2,775,009

PUMP MECHANISM FOR TYPE CASTING MACHINES Filed Aug. 14, 1953 4 Sheets-Sheet 4 l am [IE Na 59 N L /7 NB y 2,775,009 PUMP MECHANISM FOR TYPE CASTING MACHINES 7 Edward Charles Meldrum, Redhill, and Alfred Edward Roper, Morden, England, assignors to The Monotype Corporation Limited, London, England, a British cor poration Application August 14, 1953, Serial No. 374,386 Claims priority, application Great Britain May 26, 1953 4 Claims. (Cl. 22--70) This invention relates to pump-operating mechanisms for individual-type casting machines and is intended for use on machines which are sold under the registered trademark Monotype. I i

The most widely known Monotype type-casting machines designated throughout the printing industry as composition casters are furnished with a matrix case containing an assembly or fount of matrices Which is selectively positioned over a type-mould, under the control of a pre-prepared controlling ribbon, whereas the class of machine sold under this trademark, to which the present invention relates employs a carrier or holder for a single matrix, from which any requisite number of repeated casts can be made. These latter machines are intended to produce what are known in the printing industry as sorts or display type to be set by hand and the range of type sizes may extend from say, 12 typographical points up to 72 points, or over.

In composition casters, casting may be at the rate of 160 per minute, whereas in machines for casting sorts" or display type to which the present invention is applicable, the rate of casting is progressively slowed down, that for type bodies of, say fromsizes of 48 points and 72 points the rate of casting for satisfactory type bodies is reduced to 15 bodies in two minutes.

In order that machines for casting sorts or display type bodies will produce satisfactory type bodies through such a large range of body sizes, provision has to be made for overcoming difliculties which arise through varying conditions. For example, the pump-nozzle seating in the mould cannot be varied in practice and therefore the opening in the nozzle itself must be increased as the size of type increases and for the largest sizes this results in the walls of the pump nozzle being exceedingly thin and liable to chill between casting operations; also the power applied to the pump piston must be varied, and the speed of casting must be capable of wide variation. This known pump-operating mechanism comprises two levers, linked together intermediate their ends, and coupled respectively, one to the pump body and the other to the pump piston, which levers are first moved in unison by a driving rod and are then moved relatively to each other to operate the pump piston, and spring-operated pump-body elevating levers which seat the nozzle in a mould. In this existing mechanism the nozzle is moved into a seating in the base of the mould by the action of a spring and under the control of a steadily driven member. It has been found that when running at this low speed there has been a tendency for the nozzle not to seat properly in the mould, thereby giving rise to leakage of metal between the mould seating and the pump nozzle resulting in the production of imperfect type bodies.

It is the chief object of the present invention to prevent this leakage of metal between the seating in the mould and the pump nozzle.

According to the present invention, there is provided a detent or latch which acts to interrupt temporarily the upward movement of the spring-operated pump-body elevating levers, whilst the operating spring continues to be loaded, and on the release of the latch or detent, by the nited States Patent-O continued movement of the pump driving mechanism the pump body elevating levers are given an accelerated movement by their operating spring during the final stage of their travel to seat the pump nozzle in the mould slightly in advance of the operation of the pump piston.

The accompanying drawings shew well-known pump controlling mechanism for the existing type-casting machine and embodying mechanism according to the present invention:

Fig. 1 is a diagrammatic side elevation, partly in section, of the known mechanism for seating the pump nozzle and shews part only of the mechanism according to the invention, for the purpose of illustrating the mannerin which said mechanism co operates with the existing pumpoperating mechanism.

Fig. 2 is a fragmentary plan view, to a larger scale than F ig. 1 of the pump-nozzle elevating mechanism, the pumppiston operating mechanism and the mechanism according to the invention for temporarily delaying the seating of the pump-nozzle in the type mould.

Fig. 3 is a perspective View of the mechanism shewn in Fig. 2, part of the nozzle elevating mechanism being omitted.

Fig. 4 is a view approximately on the line IV--IV of Fig. 2, shewing the mechanism according to this invention, and

Fig. 5 shews the mechanism of Fig. 4 as viewed from the left hand side of that figure.

It is considered sufficient for the purposes of this specification to refer only briefly to those parts of the earlier mechanism with which the present invention is more immediately connected, as reference can be made to the prior specification above referred to for a detailed description thereof.

These parts of the pump body B, the pump piston P, the molten metal injecting nozzle N carried on an arm B of the pump body and communicating with the metal well thereof, a rocking lever N N pivoted at N and engaging the extension B beneath the nozzle N to elevate the nozzle into its operative position in engagement with a seating M in the mould M. The pump body B is elevated by a rocking lever N pivoted at N to the machine frame and rocked in unison with the lever N N by an actuating rod N spring loaded downwardly to elevate the nozzle into its operative position by an operating spring N anchored at its lower end to the machine frame. The

actuating rod N is moved upwardly once during each cycle of operation of the machine, to withdraw tthe nozzle from its operative position, by a rod N which is reciprocated vertically once during each cycle of operation of the mach ne by a cam on a driving shaft and which, in descendmg, bears against a face It on a rocking control lever N pivoted at N and engaging by its other end beneath an abutment N on the rod N The mechanism for controlling the elevation of the nozzle N by the spring N also serves to operate the piston of the pump to inject the molten metal into the mould after the nozzle N has been properly seated therein. The present invention does not concern the mechanism for operating the pump piston but as the two mechanisms are co-related the following description of the pistonope rating mechanisms will assist an understanding of the entlre mechanism. This piston-operating mechanism comprises a pair of levers P and B connected intermediate their ends by a link P (see Fig. 3) lever B being connected by one end at B to the pump body B and lever P being connected atone end at P to a piston rod P carrying at its lower end the piston P. A head B secured to a vertically movable rod B is connected to the power end of the lever B at B A head D (see Figs. 2 and 3) secured to a driving rod D is provided with an offset D which engages a compression spring P which in turn engages a nut P on a rod P connected at its lower end at P to the power end of the piston lever P The driving rod D carrying the head D at its upper end is provided at its lower end with an arm D which engages a spring D which bears against a collar on the rod B The pump actuating mechanism is driven by a cam (not shown) on the main driving shaft of the machine and operates upon the driving rod D to elevate the head D and with it the head B through the intermediary of the arm D acting on the spring D Elevation of these heads raises the power ends of levers P and B and also the stud N which is carried on an extension D of the head D, thereby permitting the end of the nozzle control lever N engaged by the stud N to rise under the action of the spring N acting on the rod N which is accordingly pulled downwards to rock the lever N N and lever N to elevate the nozzle N into position in the mould seating M The driving rod D continues to rise until a stop D on the lower end thereof meets a variable abutment D thus arresting the movement of the head B and of the pump body lever B Continued upward movement of the driving rod D separates the head D from the head B and the spring P is thereby compressed by the offset D on head D.

The energy is stored in the spring P and is suddenly released and the spring P acts on the rod P through the nut P to rock the piston lever P to inject the metal into the mould in timed relation to the seating of the pump nozzle in the mould. To the head B is secured a rod 13 (Fig. 3) upon which is mounted a vertically movable sleeve P (see Fig. 4) provided with an arm P slideable on the rod P and occupying a position between the offset D of head D and the piston-operating lever P The sleeve P is provided with a retracting spring P and with a shoulder P positioned to engage the lower or vertical arm of a latch P which is pivotally attached to a collar P adjustably secured to the upper end of the rod B The pivot of the latch P is located above and in line with the shoulder P When the sleeve P occupies its normal or retracted position, the engaging arm of the latch stands above and in line with the upper face of the shoulder P being held in this position by a spring (not shown) sleeve P and lever P can thereby be arrested with the head B by the abutment D The latch is also provided with a tripping arm P located in the path of, and at a distance above, an abutment on the part D of the head D. The abutment is constituted by a plurality of leaves P (see Figs. 3, 4 and 5) carried on the head D and secured thereto by a winged screw P The leaves can be moved into and out of position beneath the arm P and thereby provide for the adjustment of the gap between the part D and the arm P of latch P and so determine the amount of travel permitted the head D after head B has been arrested by the abutment D and consequently the degree of compression applied to the spring P before it is permitted to act upon the piston lever P for until latch P is engaged and moved out of contact with the shoulder P the separation of the levers P and B at their power ends is prevented, although they are free to move in unison for permitting the elevation of the pump and the seating of the nozzle. This graduated abutment P is essential to provide suificient driving power in the spring P to ensure a full charge of metal entering the mould with pump nozzles leaving openings of diiferent sizes, used according to the sizes of the type bodies to be cast.

The operation of this mechanism is as follows:

The driving rod D and the two heads B and D move in unison until the abutment D arrests the head B and with it the pump body lever B together with the piston lever P the latter being for the time being locked to head B by the engagement of the latch P with the sleeve P The head D is, however, free to continue its motion and in so doing compresses the spring P until, by the engagement of the leaves P with the tripping arm P the latch is finally withdrawn from the shoulder P The piston lever P is thereby unlocked, whereupon the power stored in the spring P is suddenly applied to the piston to force the molten metal into the mould.

Although the rod D is arrested when the stops D strike the abutment D the rod B continues to rise until the piston lever P has operated the pump piston, but as the piston lever P is connected to the pump body lever B through the link P this later upward movement of the rod B tends to lift the lever B and through it the pump body to hold it against the downward pressure of the piston and thus hold the pump nozzle firmly in its seating in the mould. The rocking control lever N is held depressed by the stud N on the driving head D so as to hold the nozzle away from the mould. As the driving head rises, stud N rises to release the armN and so move the nozzle into the seat in the mould under the action of the spring N As the head descends the stud N again depresses the arm N to move the nozzle away from the mould and into the molten metal in the metal pot in which the pump is situated and prevent chilling of the nozzle. The stud N is adjustably mounted in the arm D of the head so that the timing of the nozzle movement can be accurately adjusted. Since the head D is driven from a cam on the main driving shaft of the machine, the motion of the stud N is a smooth reciprocating motion which gives a controlled steady movement of the nozzle into the mould seat.

The mechanism of the present invention serves to hold the arm N depressed when the head D and stud N rise, so as to delay temporarily the seating of the nozzle in the mould. The arm N is subsequently released with a sudden action so that the nozzle is accelerated into the seating in the mould by the delayed action of the spring N, which action is no longer opposed by the stud N. The increased driving force thus given to the nozzle ensures the accurate .seating of the nozzle in the mould and breaks up or disperses any metal which may have congealed on the surface of the nozzle, and which would otherwise prevent a perfect joint between the nozzle and the mould.

This delay mechanism consists of a cranked lever N N (see Fig. 5) pivoted to the machine frame at N and having secured to its lower arm N by screws N a detent N arranged to co-operate with an additional face nit formed on the arm N The other arm N of the cranked lever is pivoted at N to a slide N vertically movable between guides N and N secured to the machine frame by screws N and holding plates N The cranked lever N N is springbalanced to the position shown in Fig. 5 in which the detent N acts on the face 111 of the control lever N to hold the latter depressed. This spring balancing is effected by a spring N anchored to a stud N on the lower 7 holding plate N and connected at its other end to a stud N on the slide N Stud N also serves as a stop cooperating with the upper plate N to limit the downward movement of the slide N to position accurately the detent N with respect to the face 111. The action of the spring N is balanced by a spring N connected with an anchoring stud N on the upper holding plate N and a stud N at the lower end of the slide N A catch N is pivoted to the upper holding plate N and N and co-operates with a stud N carried on the slide N near its top end to hold the slide raised with the detent N displaced out of co-operating relation with the surface nl on the control lever N By this means the mechanism according to the present invention can be rendered inoperative when desired so that the machine can be operated in the existing manner in which the stud N alone co-operates with the control lever N At its upper end slide N is formed with a projection N (see Fig. 4) overhanging the extensions p of the existing abutment leaves P carried on the head D for cooperating with the arm P of latch P. A screw-threaded adjustable stop N is threaded into the projection N and carries at its upper end and secured thereto by nut N, a knurled wheel N This facilitates turning the threaded stop N for the purpose of adjusting it relative to the extension p on the leaves P. A leaf spring N secured to the slide N by screws N engages the knurled wheel N to hold the stop N against accidental displacement from the position to which it has been adjusted. Adjustment of the stop N will vary the timing of the operation of the nozzle as will hereinafter appear.

The operation of the mechanism according to the invention is as follows:

As the head D is raised, head B and sleeve P will rise together until the stop D meets the abutment D During this movement the pump piston lever P and the pump body piston B will also rise but, as the rocking control lever N is held depressed by the detent N the nozzle is not permitted to rise into engagement with the mould seating. When the stop D reaches the abutment D the movement of the head B and of the sleeve P is arrested and continued movement of the head D compresses the spring P storing energy which is subsequently expended in imparting stroke to the pump piston to inject the molten metal into the mould. During this continued movement of the head D, and prior to the operation of the piston, the extensions 12 on the leaves P carried on the head engage the stop N on the slide N and raise the slide against the action of spring N so as to rock the cranked lever N N clockwise as shewn in Fig. 5, thereby displacing the detent N out of engagement with the face n1 on the control lever N. The latter is thereby released and the spring N is permitted to pull downwardly the rod N and so accelerate the movement of the nozzle N rapidly into the mould through the intermediary of the rocking lever N N and the lever N Further continued movement of the head D causes the leaves P to strike the arm P of the latch P thereby releasing the sleeve P for upward movement under the action of spring P to impart stroke to the pump immediately after the seating of the nozzle in the mould as hereinbefore described.

As the head D descends, the sleeve P is lowered and latch P resets itself on the shoulder P and the slide N falls, thus allowing the cranked lever N N to be returned by its springs towards the balanced position. As the head D completes its downward travel the stud N depresses the arm N and permits the detent to reset against the face 111.

What we claim is:

1. In a pump-operating mechanism for individual-type casting machines, a pump body, a nozzle thereon, a piston operable in said body, pump body elevating means comprising rockable levers supporting said pump body and a spring acting on said levers to elevate said body to bring said nozzle to an operating position, piston operating means comprising two levers linked together intermediate their ends and coupled one to said pump body and the other to said pump piston, driving means operative on said linked levers to move said levers in unison, an abutment connected to said lever coupled to the pump body and a stop arranged to engage said abutment and arrest said lever coupled to the pump body whereby continued movement of the lever'coupled to the pump piston operates said piston, and means for temporarily interrupting the movement of said nozzle to the operating position, said means comprising a detent operative on said pump elevating levers to prevent operation thereof, and an abutment on said driving means arranged to release said detent at a predetermined point in the cycle of operations of said driving means, whereby said pump elevating levers are given an accelerated movement by the spring acting thereon to accelerate the nozzle to the operating position.

2. In a pump operating mechanism for individual-type casting machines, a pump body, a nozzle thereon, a piston operable in said body, pump body elevating means comprising rockable levers supporting said pump body and a spring acting on said levers to elevate said body to bring said nozzle to an operating position, piston operating means comprising two levers linked together intermediate their ends and coupled one to said pump body and the other to said pump piston, driving means operative on said linked levers to move said levers in unison, an abutment connected to said lever coupled to the pump body and a stop arranged to engage said abutment and arrest said lever coupled to the pump body whereby continued movement of the lever coupled to the pump piston operates said piston, and means for temporarily interrupting the movement of said nozzle to the operating position, said means comprising a pivoted control lever acting on said pump elevating levers to control the elevation of the pump, a rockable cranked lever, a detent carried on one arm of said lever and acting on said control lever to prevent movement of said nozzle to the operating position, and a vertically movable slide and a pivot connexion between said slide and the other arm of said cranked lever, said driving means for said linked levers including an abutment arranged to engage said slide at a predetermined point in the cycle of operation of said driving means, whereby to displace said slide and release said detent from engagement with said control lever to accelerate said nozzle to the operating position.

3. In mechanism as claimed in claim 2 the combination with said slide of opposed springs acting thereon to hold said slide in a balanced position with said detent co-operatively aligned with said control lever, and a latch operable to hold said slide displaced from the balanced position and with said detent displaced from its position of co-operating alignment with said pivoted control lever.

4. In a pump-operating mechanism for individual-type casting machines, a pump body, a nozzle thereon, a piston operable in said body, pump body elevating means comprising rockable levers supporting said pump body and a spring acting on said levers to elevate said body to bring said nozzle to an operating position, piston operating means comprising two levers linked together intermediate their ends and coupled one to said pump body and the other to said pump piston, a driving rod, separate driving means for each of said linked levers, said driving means being driven by said driving rod and operative on said linked levers to move them in unison, an abutment connected to said lever coupled to said pump body and a stop arranged to engage said abutment and arrest said lever coupled to the pump body whereby continued movement of the lever coupled to the pump piston operates said piston, and means for temporarily interrupting the movement of said nozzle to the operating position, said means comprising a pivoted control lever acting on said pump elevating levers to control the elevation of the pump, a rockable cranked lever, a detent carried on one arm of said lever and acting on said control lever to prevent movement of said nozzle to the operating position, and a vertically movable slide and a pivot connexion between said slide and the other arm of said cranked lever and an abutment on said driving rod arranged to engage said slide at a predetermined point in the cycle of operation of the driving rod, whereby to displace said slide and release said detent from engagement with said control lever to accelerate said nozzle to the operating position, a stop carried on said slide, said abutment comprising a plurality of sleeves individually movable into alignment with the stop, said stop being adjustable to vary the point in the cycle of operation at which the detent is released.

References Cited in the file of this patent UNITED STATES PATENTS 633,088 Lanston Sept. 12, 1899 674,374 Bancroft May 21, 1901 1,927,764 Willis Sept. 19, 1933

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