US3024505A - Foundry sand rammers - Google Patents

Description

March 13, 1962 A. s. BEECH 3,024,505

FOUNDRY SAND RAMMERS Filed Feb. 24, 1959 3 Sheets-Sheet l A. S. BEECH FOUNDRY SAND RAMMERS 3 Sheets-Sheet 2 Ill" March 13, 1962 Filed Feb. 24, 1959 /////i 1/ V \N March 13, 1962 A. s. BEECH FOUNDRY SAND RAMMERS 5 Sheets-Sheet 3 Filed Feb. 24, 1959 L a A Q NM R 0 Q wm Q \S Q 6 QM M Q m y 1 w wk MK E: L R M h r \m Q w N m m/ $0 9 k \QQ\ .m MW. P \Nm m WW. R. @Q

United States Patent 3,024,505 FOUNDRY SAND RAMMERS Austin Sidney Beech, Leighton Buzzard, England, as-

signor to Foundry Equipment Limited, Bedtordshire,

England, a British company Filed Feb. 24, 1959, Ser. No. 795,194 Claims priority, application Great Britain Feb. 25, 1958 3 Claims. (Cl. 22-36) The invention relates to foundry sand rammers of the kind in which a rotating impeller flings wads of sand downwards into a mould, the impeller being mounted in a casing which forms a ramming head and which is movably mounted so that it can be displaced by the operator to any desired position over the mould.

It is an object of the present invention to provide means whereby the effort of the operator in moving the ramming head to a desired position is minimised. In this connection it will be understood that the ramming head has to be driven by a powerful motor and, as ramming is rapid, foundry sand must be conveyed to the ramming head by a conveyor mounted on the part which carries the head and all these parts add up to a considerable weight, so that both friction and the inertia of the parts have to be overcome to effect movement.

According to the present invention a foundry sand rammer comprises in combination a ramming head, a swinging arm carrying said head, a pivotal mounting for said arm, a hydraulic motor connected to said arm for swinging it about its pivotal mounting and control meansfor the hydraulic motor enabling an operator to cause the hydraulic motor to swing the arm in either direction at will.

In one construction in accordance with the invention the hydraulic motor is a vane-type motor having a rotatable driving member co-axial with and directly connected to the swinging arm. The pivotal mounting of the swinging arm may be supported on a second swinging arm which itself has a pivotal mounting, a hydraulic motor for swinging it about its pivotal mounting and control means enabling the operator to cause the hydraulic motor to swing the second swinging arm in either direction at will.

The control means for the hydraulic motor or motors may consist of a solenoid operated hydraulic controlvalve or valves, and switch means on the ramming head such that movement of the switch means in the desired direction of movement of the head will cause movement of the hydraulic motor to swing the arm or arms in the direction or directions which will effect said desired movement. Preferably the switch means on the ramming head comprise a support fixed to the head which carries four contacts facing in four directions and a yieldingly mounted handle surrounding the contacts so as to be movable into engagement with any one of them by pressure in the appropriate direction.

The following is a description by way of example of one construction of foundry sand ramming machine in accordance with the invention, reference being made to the accompanying drawings in which,

FIGURE 1 is a side elevation of the machine with part of the exterior broken away to show the internal con- Referring to FIGURES 1 and 2, the machine comprises a base 11 on which is secured an upstanding column indicated in dotted lines at 12 over which is a rotatable sleeve 13 mounted on ball bearings on the column. On top of the sleeve 13 there is mounted the casing 14 of a vanetype hydraulic motor of which the internal vane is secured to the column 12. The sleeve 13 is rigidly connected to side plates 15 on each side of it which form part of a rotatable casing from which projects swinging arm 16. The casing also is extended upwardly to form a bracket 17 on which is mounted a belt conveyor 18 driven by an electric motor 19. The belt conveyor slopes upwardly from an inlet at 20 above the column 12 to an outlet 21 which is located above the outer end of the swinging arm 16.

At the end of the swinging arm 16 on the axis 22, which is immediately below the delivery 21 of the conveyor 18, there is a pivotal mounting for a second swinging arm 23 which extends outwardly to a ramming head 24. Above the arm 23 is a secondbelt conveyor 25 having a receiving end 26 below the delivery 21 of the first conveyor and the belt conveyor 25 delivers sand into the ramming head 24 which has a tangential outlet through which sand is flung downwardly into any moulding box which may be located by the foundryman below it. The second swinging arm 23 carries on the other side of its pivot a driving motor 28 for the ramming head, which is also connected by appropriate gearing, the details of which are not shown in the drawing, to drive the belt conveyor 25. This gearing and the internal construction of the ramming head are well known per se. The weight of the motor 28 balances the weight of the ramming head 24 about the pivotal axis 22.

A hydraulic motor 30 is mounted in the end of the swinging arm 16 for turning the arm 23 about its pivotal axis. This motor is shown in section in FIGURE 3 and comprises a central shaft 31 which carries a vane 32 and the side of which bears on a circular fixed abutment member 33. The abutment member is grooved to receive rubber backing strips at 34, where it abuts on the outer wall of the motor 30, and at 35 where it abuts" on the rotor shaft 31. On one side of the abutment 33 there is a pipe connection 36 and on the other side a pipe connection 37.

vBy connecting 36, 37 to an appropriate control valve on a hydraulic pressure supply, pressure may be admitted to either side of the abutment 33, the other side being connected to exhaust and the rotor shaft 31 can thereby be caused to rotate through nearly a whole revolution in either direction. The construction of the hydraulic motor 14 is similar to that of the motor 30, with the exception that there may be two vanes and two abutments as indicated in chain lines in FIGURE 3 at 38, 39. In this case there are also two additional pipe connections 40, 41, the connection 41 being interconnected with 36 and the connection 40 with the connection 37. This enables the swinging arm 16 to be impelled with a stronger force but through a smaller arc of movement than the arm 23.

On the ramming head 24 there are mounted two control arms 42, 43. These are similar in appearance and location to the solid control arms normally fitted on the ramming heads of machines of the kind herein described, when their movements are hand-actuated, but in the present case the control arms 42, 43 contain internal electrical connections which are such that pressure by the operator on the arms in the direction in which he desires the ramming head to move, will cause the hydraulic motors 14 and 30 to move the arms in the desired direction. The electrical connections control the hydraulic motors through relay actuated solenoid control valves.

Hydraulic pressure is supplied from a tank 44 by a pump 45 driven by a motor 46 overhung from the back of the casing 15 and it will be noted that as the motor 46 and pump 45 are mounted on the casing 15 all the hydraulic connections are concentrated in the casing and in the arm 16 which projects from it, so that flexible hydraulic connections are not necessary. The control of the various electric motors is effected by pushbuttons 47, 48, 49 mounted on the ramming head 24 and the solenoid-operated control valves are accommodated in boxes 50, 51 on the sides of the arm 16 in close association with the pipework from the pump 45.

The internal construction of the arms 42, 43 is shown in FIGURES 4 and 5. Bracket members 52, 53 extend outwardly from the ramming head one above the other and support clamps 54, 55 to the upper and lower ends of the handle 42 which is composed of a piece of flexible rubber hose held in the clamps at the top and bottom. Within the rubber hose there is mounted a longitudinally extending contact tube 56 which is secured to the walls of the hose. Inside the contact tube and spaced therefrom is an insulating tube 57. On the tube and opposite to four parts of the tube 56 is an upper row of grounding contacts 58 and a lower row of switch circuit contacts 59, there being four contacts in each row corresponding to the four contacts on tube 56 on the hose. The four contacts 59 are connected to four separate electrical leads leading to solenoid-operating relays shown in FIGURE 7, and the four contacts 58 are in electrical connection with ground through the bracket 52. If the operator presses the handle 42 in any one direction, that is to say left or right or away from him or towards him, it will bring a corresponding pair of the contacts 58, 59 into connection with the part of the tube 56 which is nearest to the direction of pressure by the operator and will complete the circuit of the corresponding relay winding to ground. If the relays are appropriately connected to the solenoid-operated control valves, the result will be that the hydraulic motors will move the ramming head in the direction in which the operator is applying pressure. The manner in which the hydraulic and electrical connections are effected to bring this result about is shown in FIGURES 6 and 7.

Referring to FIGURE 6, the hydraulic and other parts are given the same reference numbers as they bear in FIGURES l and 2, insofar as they are shown in those figures. The pump 45 draws from the reservoir 44 through a filter 60 and it delivers into a main delivery pipe 61 from which a branch 62 extends through a flow control valve 63 and a pressure relief valve 64 to a solenoid-operated hydraulic reversing control valve 65. The valve 65 is a four-way valve having a connection 66 which extends back to the tank 44 and two connections 67, 68 which extend to the hydraulic motor 14. A dual pressure relief valve 69 is connected between the pipes 67, 68 so that in the event of any excessive pressure difference between the pipes in either direction the excess pressure will be unloaded. The solenoid-operated reversing valve 65 has two magnet windings (not shown in FIGURE 6 but indicated in FIGURE 7 at 70, 71). When the winding 70 is energised the reversing valve 63 is moved to such a position that pressure will be applied to the motor 14 to move the arm 16, as viewed by the operator standing in front of the ramming head 24, away from him. When the winding 71 is energised the arm 16 will swing toward the operator (the arm is normally at an angle to the operator). Accordingly, the windings 70, 71 are connected to the relays operated by the contact strips 56, FIGURES 4 and which lie respectively in front of and behind the handle 42, because when the operator presses the rubber hose 42 away it brings the front contact strip into engagement with its corresponding contacts 58, 59 (which will make the head 42 move backwards) and when he pulls it forward it brings the rear contact strip into action (which will make the arm 16 move in a. direction to bring the head 24 forwards).

Another branch 72 from the delivery pipe 61 passes through a flow control valve 73 to another solenoidoperated valve 75 similar to the valve 65 already described and actuated by two magnet windings 80, 31 (FIGURE 7). From the reversing valve 75 there extends a pipe 76 which joins the pipe 66 to the tank and two pipes 77, 78 which are connected to the inlets to the rotor vane-type motor 30 which operates the swinging. arm 23. Here again there is a dual pressure relief valve 79 corresponding to the valve 69 already described. The magnets 80, 81 are energised by relays controlled by those contacts 59 in the handle 42 which lie respectively to the right and to the left of the handle as viewed by the operator. Thus pressing the handle to the left (and so closing righthand contact 59) will operate winding which causes arm 23 to swing to the left, while if the handle is pressed to the right, the arm will be made to swing to the right.

The electrical connections are shown in FIGURE 7 and it will be seen that the connection of the handles 42, 43 are indicated in the diagram as being in parallel with each other so that either handle has the same effect. Only the connections of the lefthand handle will be followed out in the following description.

The electrical supply for the solenoid-operated valves is taken from leads 90, 91, the lead extending to the terminals of the solenoid windings and the lead 91 to the solenoid windings through the relay contacts r1, r2, r3, 24. The relay contacts are closed by relay windings R1, R2, R3, R4 which are connected respectively to the four contact strips 59 of the handle 42. The fore and aft contacts are connected to the relay windings R1, R2 respectively by lines 92, 93 through reversing relay contacts 15. The relay contacts 15 are operated by a relay winding R5 in the circuit of a direction selection switch 94 hereinafter referred to. The supply to the relays R1, R2, R3, R4 is from a low-voltage secondary winding 95 of a transformer 96 connected across the mains 90, 91.

The circuit proceeds by way of line 97, switch 98 and line 99 (which may be grounded) to the central terminals 58 of switches 42 and 43 and there is a common return line 100 from the relay windings to the other terminal of the transformer.

As has already been explained, the arm 16 of the sand ramming machine normally lies at an angle to the operator either to his left or to his right, and the object of the direction selection switch 94 is to ensure that if the arm 16 is extending to the right of the operator the hydraulic motor 14 will be operated in a direction to move the head towards him and that if it is extending to the left of the operator it will still be operated to move the head towards him, if he pulls the handle 42 towards him. To this end it is necessary to reverse the operation of the relays R1; R2, at the moment when the arm 16 crosses over from the righthand to the lefthand position. The direction selection switch 94 is shown in FIGURE 1 as mounted on the end of the arm 16 and provided with a connection to the arm 23 which will operate it as the crossover occurs.

The left and righthand contacts 59 of switch 42 are connected to the relay windings R3, R4 which control solenoid windings 81, 80 respectively.

The switch 98 is a two-way switch which in one position connects the transformer 95 to the line 99 and handles 42, 43, and in the other position is connected to a line 101 which leads to a controlling cable coupled to a selector switch 102 having four terminals in parallel with the four terminals 59 of switches 42 and 43 and operated by an appropriate handle. This permits the machine to be controlled from a distance if desired.

I claim:

1. In a foundry sand rammer the combination of a ramming-head, a swinging arm carrying said head at its end, a pivotalmounting for said arm, a hydraulic motor connected to said arm for swinging it about its pivotal mounting, an electromagnetisally-operated hydraulic valve connected to said hydraulic motor to control its movements, switch means on the ramming head having a movable control member so mounted as to be movable in a transverse direction to the length of the swinging arm, and electrical connections from the switch means to the said electromagnetically-operated valve, the connections being such that urging the control member by the operator transversely in either direction of movement, will operate the switch means to cause it to energize the electromagnetically-operated hydraulic valve in the manner which causes the hydraulic motor to move the swinging arm in the same direction as that in which the control member has been urged.

2. A foundry sand rammer comprising the combination of a base, a first swinging arm pivotally mounted on said base, a second swinging arm pivotally mounted on the first swinging arm, a ramming head mounted on the outer end of the second swinging arm, a first hydraulic motor connected to the base and to the first swinging arm for swinging the arm about its pivotal mounting, a second hydraulic motor connected to the first swinging arm and t0 the second swinging arm for swinging the second swinging arm relatively to the first swinging arm; a first electromagnetically operated hydraulic valve connected to the first hydraulic motor to control its movements, a second electromagnetically-operated hydraulic valve connected to the second hydraulic motor to control its movements, switch means on the ramming head having a movable control member so mounted as to be movable in two horizontal dimensions, electrical connections from the switch means to both electromagnetically-operated valves,

the switch means and electrical connections, to the first electromagnetically-operated valve being such that, assuming the two arms are at an angle to one another, urging the control means in the direction of the length of the second swinging arm causes the first hydraulic motor to move the first swinging arm in such a direction as to move the ramming head substantially in the direction in which the control means is urged, and the electrical connections to the second valve being such that urging the control means in a direction transverse to the length of the second swinging arm causes the second hydraulic motor to move the second swinging arm in the direction in which the control means is urged.

3. A foundry sand rammer as claimed in claim 2 wherein said electrical connections to the first electromagnetically-operated hydraulic valve include a reversing switch and an operative connection therefor to the pivotal mounting of the second arm on the first to reverse the direction in which the valve causes the first hydraulic motor to operate Whenever the swinging arms pass the position in which they are in line with each other.

References Cited in the file of this patent UNITED STATES PATENTS 2,025,981 Getty Dec. 31, 1935 2,163,070 Stringer June 20, 1939 2,212,510 Clay et al. Aug. 27, 1940 2,691,194 Koren Oct. 12, 1954 2,752,463 Staak June 26, 1956 2,752,647 Beech July 3, 1956 2,793,623 Ludwig et al. May 28, 1957 2,902,009 Ludwig et al. Sept. 1, 1959

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