GB2177151A

GB2177151A - Latching mechanism

Info

Publication number: GB2177151A
Application number: GB08516029A
Authority: GB
Inventors: Melvin Stuart Wilson
Original assignee: TOLLEMACHE Ltd
Current assignee: TOLLEMACHE Ltd
Priority date: 1985-06-25
Filing date: 1985-06-25
Publication date: 1987-01-14
Also published as: EP0206648A2; EP0206648A3; ES556149A0; GB8516029D0; ES8706909A1; GB2177151B

Abstract

A container is secured to a compactor by a hooked latch arm (21) which is adapted to be both swung inwardly and to be retracted to engage and draw a container against the compactor outlet. An over centre linkage arrangement (A,B,C,) is provided between the latch arm and a motor 28 whereby the loads on the drive motor (28) are relieved when the latch arm (21) is fully retracted. Cam surfaces 60, 61 on the latch arm cooperate with a plate 41 and a roller 44 to cause swinging movement of the hooked latch arm. <IMAGE>

Description

1 GB2 177 151A 1

SPECIFICATION

Latching mechanism 0 1 45 p This invention relates to a latching mechanism and more especially to a latching mechanism for securing a container to a compactor.

In large industrial compactors it is necessary to be able to secure the container for example a roll-on-roll-off container or a fixed height body type container over the exit from a compactor chamber so that upon operation of a large ram the container is filled with material displaced from the compactor chamber.

Typically, such a compaction process is required when loading containers with compressible waste material or rubbish or other compressible material.

The problem arises that one wants auto- matically to take care of any slight misalignments of the container with the compactor and then to draw and hold the container into tight sealed relationship to the end on the compactor to enable the material to be forced from the compactor chamber into the container.

The object of the present invention is to provide an improved latching mechanism which utilizes a latch arm which can function not only to hold the container against the compactor in a reliable manner but also to take care of any fine alignment necessary of the container with the compactor.

According to the present invention there is provided a latching mechanism for securing a container to a compactor comprising a body adapted to be secured to the compactor, a hooked latch arm guided for sliding movement by said body between a retracted position in which it is adapted to engage and hold a container in engagement with the compactor and an advanced position to release such a container, and drive means for moving said latch arm between its retracted and advanced positions, said latch arm being mounted to said body by a pivot means adjacent its rear end guided for movement longitudinally of said body and comprising cam surfaces on opposite sides thereof cooperable with said body whereby said latch arm is swung about said pivot axis for inward movement towards and outward movement away from said container upon retracting and advancing movement respectively of said latch arm, and said drive means comprising a linkage connecting the pivot means with a drive motor and including a connection to the body whereby an overcentre arrangement releases loading on the drive motor when the latch arm is fully re- tracted.

Conveniently, the linkage may comprise first and second links, the first link being pivotally mounted intermediate at its ends to the body, having one end connected to a reciprocable motor and having its other end connected to one end of the second link, the other end of which is connected to said pivot means.

Generally, with this arrangement the operation of the motor when the latch arm is in its extended position causes the latch arm initially to swing from an outwardly disposed position towards the container so as to engage the container if it is misaligned and align it with the compactor outlet, subsequent completion of movement of the latch causing the latch hook to engage a keeper member on the container and draw the container into tight engagement with the compactor. preferably the motor means is fluid powered and may conve- niently be a hydraulic jack.

A particularly simple linkage is provided in the preferred instruction in which the links are each bellcranks with the over-centre arrangement being provided by the axes pivotally connecting the ends of the second link being positioned nearer the base of the body to be secured to a compactor than the axis of the povotal connection between the first link and the body in the retracted position of the latch arm, and being arranged to pass through an aligned position upon initial movement of the motor means to advance the latch arm from its retracted position.

By having the over-centre arrangement it is ensured that once the container is drawn into its required position attached to the compactor the loading on the hydraulic jack or other motor means is relieved due to the fact that the principal forces required to retain the con- tainer on the compactor during compaction of material in the container are held by the shear force across pivot connections provided between the linkage and the latch base.

The invention will be described, by way of example, with reference to the accompanying drawings in which:

Fig. 1 shows a latch embodying the invention in association with a compactor for use with roll-on-roll-off containers; Fig. 2 shows a latch embodying the invention in association with a compactor for use with fixed body height type containers; Fig. 3 is a side elevational view of the latch as used with the compactor of Fig. 2; and Fig. 4 is a plan view of the compactor shown in Fig. 3.

Referring to Fig. 1, a compactor is shown comprising a ram assembly 50 associated with a chamber 51 on opposite sides of which are mounted backing mechanisms 53. As shown in Fig. 2 the latching mechanism is mounted approximately mid-way up the side of the compactor chamber for association with fixed height type containers.

The latching mechanism as shown in Figs. 3 and 4 comprises a body formed of a base 25 provided with upstanding pairs of flanges 26 and 27. The latching mechanism comprises a latching hook arm 21 which is shown in the full line illustrations of Figs. 3 and 4 in its 2 GB2177151A 2 retracted position in which the hooked portion of the arm engages over a keeper member 23 attached to the container 22. The edge of the container is drawn into engagement with a resilient buffer 24 around the periphery of the opening from the compactor chamber 51.

Pivotally mounted to the flanges or lugs 26 is a hydraulic jack 28 provided with a piston 29 the end of which is connected by a pivot pin 30 to one end of each of two links 31 which are in the form of bell cranks pivoted by a pin 33 at a mid point thereof to the flanges 27. The other ends of the links 31 are connected by pins 32 to one end of each of a pair of second bell crank links 34 the other end of which is connected to a pivot pin 35 connected to the rear end of the latch arm 21 and guided for movement longitudinally of the latch body by being received in guide slots 36 in the flanges 27.

As will be noted from Fig. 4, with the jack 28 in its extended, latch arm retracting posi tion, the linkage is arranged such that the pi vot pin 32 is in a position B such that the line between the axes of the pivot pin 32 in the position B and the pivot pin 35 in a position C are nearer the base 25 than the pivot pin 33 at position A. As a consequence upon retraction of the jack 28, the pin 30 will be drawn back causing the bell crank link 31 to 95 pivot in a clockwise direction so that the pin 32 passes from the position B through a cen tral position aligned with the pivot pin 35 to cause the pin 35 to be moved forwardly along the guide slots 36 to advance the bell crank 100 on 21 towards the position 2 1' in order to disengage the keeper 23 on the container.

Continued movement of the hydraulic jack will cause continued movement of the pivot 35 towards the forward end of the guide slots 36 until the latch arm 21 has both been ad vanced and swung outwardly away from the container to the position shown at 21" in Fig.

4. The outwardly swinging movement of the latch arm 21 as it is further advanced is 110 caused by the action of two cam surfaces 60 and 61 near the rear end of the latch arm which cooperate with the body to cause the outwardly swinging movement of the latch ar ' m. As will be appreciated from Fig. 4 these cam surfaces 60 and 61 are in the form of inwardly bent or shaped portions of the rear end of the latch arm.

The innermost cam surface 60 engages a wear plate 41 secured via plate 42 to a mounting channel 19. The other outwardly facing cam surface 61 engages a roller or pin 44 supported by the flanges 27. As shown in Fig. 3 the weight of the latch arm 21 is sup- ported by a wear plate 40 mounted to the body.

For use one such latching mechanism is mounted on either side of the compactor. When the latch arms are in their advanced and outwardly swung and disengaged position 130 21" a container is moved adjacent to the compactor exit. The hydraulic rams 28 of each latch are then actuated and forced outwardly to cause the latch arm to be retracted by the pin 35 being drawn back along the guides 36. Initial retraction of each latch arm causes it to be swung inwardly, pivoting about the retracting pivot 35 due to the action of the cam surface 6 1. With both latch arms on opposite sides of the container being swung inwardly any misalignment of the container will be corrected by one or other of the latch arms engaging the container until the container is aligned with the compactor once the latch arms reach the position 21'. Continued movement of the hydraulic jack or motor 28 for each latching mechanism causing the latch arm 21 to be drawn back to engage the container keeper 23 and draw the con- tainer towards the compactor. At the end of the retraction movement the pivot pin 32 passes through the position of alignment with the pivot pins 33 and 35 to an over-centre position at position B as shown in Fig. 4.

With this arrangement the large forces exerted on the container during use of the compactor are transferred to the action of the pivot pins to the latching mechanism body and thus forces on the hydraulic motor which must otherwise be present during use of the compactor are relieved.

The latching mechanism shown in Figs. 3 and 4 as applied to the fixed height body container of Fig. 2 is mounted approximately at the mid point of the height of the container and comprises the single base plate 25. In the embodiment of Fig. 1 where the latching mechanism is applied for a roll-on-roll-off container usage the latching mechanism is mounted near the bottom of the compactor chamber rather than half way up its sides. However, an additional difference is shown in this construction in that instead of the latching mechanism having a single base plate 25 which is secured to the side of the compactor chamber, the mechanism comprises a series of shorter base plates which are welded between the grooves between vertical uprights on the outside of the compactor chamber as shown in Fig. 1. However, this is a simple matter of constructual convenience as to how the latching mechanism is mounted to the compactor side wall. Of prime importance is the actual mechanism by which the container engaging latch arms are intially swung in towards the container to align the same before drawing the container back against the compactor with the forces retaining the container in position during use of the compactor being taken up through the mechanical linkage mounting with the motor of the drive means being relieved from unnecessary loading.

Claims

1. A latching mechanism for securing a con- 3 GB2177 151A 3 W 10 1 i 1 tainer to a compactor comprising a body adapted to be secured to the compactor, a hooked latch arm guided for sliding movement by said body between a retracted position in which it is adapted to engage and hold a con- 70 tainer in engagement with the compactor and an advanced position to release such a con tainer, and drive means for moving said latch arm between its retracted and advanced posi tions, said latch arm being mounted to said body by a pivot means adjacent its rear end guided for movement longitudinally of said body and comprising cam surfaces on oppo site sides thereof cooperable with said body whereby said latch arm is swung about said 80 pivot axis for inward movement towards and and outward movement away from said con tainer upon retracting and advancing move ment respectively of said latch arm, and said drive means comprising a linkage connecting 85 the pivot means with a drive motor and in cluding a connection to the body, the linkage being such as to comprise an over-centre ar rangement to relieve loading on the drive mo tor when the latch arm is fully retracted. 90

2. A latching mechanism according to claim 1, wherein the linkage comprises first and second links, the first link being pivotally mounted intermediate its ends to the body, having one end connected to a reciprocal mo tor and having its other end connected to one end of the second link the other end of which is connected to said pivot means.

3. A latching mechanism according to claim 2 wherein the links are each bell cranks with the over-centre arrangement being provided by the axes of pivotal connections at the ends of the second link being positioned nearer the base of the body to be secured to a compac tor than the axis of pivotal connection be tween the first link and the body in the re tracted position of the latch arm and being arranged to pass through an aligned position upon initial movement of the motor means to advance the latch arm from its retracted posi tion.

4. A linkage mechanism according to claim 3, wherein two pairs of first and second links are provided with the second links being pivo tally connected on either side of a drive mem ber from the motor means and the second links being pivotally connected on the remote sides of the first links to use between two flanges projecting from the base of the body.

5. A linkage mechanism according to any preceding claim wherein the motor means is a fluid power motor.

6. A linkage mechanism according to claim 5, wherein the motor means is a hydraulic jack.

7. A linkage mechanism according to any preceding claim wherein the pivot means is received in and guided by slots in the flanges.

8. A linkage mechanism according to any preceding claim, wherein the guide means comprises a wear plate on said base engagable with one side cams surface of the latch arm and a roller or pin carried by the body engaging the cam surface on the opposite side of the latch arm.

9. A linkage mechanism according to any preceding claim, wherein the cam surfaces comprise an inwardly bent or shaped end of the latch arm.

10. A latching mechanism constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated Figs. 3 and 4 of the accompanying drawings.

11. A compactor comprising a pair of latches as claimed in any preceding claim mounted thereon for drawing a container into engagement with the compactor to receive material therefrom.

12. A compactor according to claim 11, wherein the latches are mounted near the mid point of the compactor side walls to adapt the compactor for use with fixed height body type containers.

13. A compactor according to claim 11, wherein the latches are mounted near the bottom of the compactor side walls for adapting the compactor to receive roll-on-roll-off type containers. 95

14. A compactor constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in Figs. 1, 3 and 4 or Figs. 2, 3 and 4 of the accompanying drawings.

Printed in the United Kingdom for Her Majesty's Stationery Office, Dd 8818935, 1987, 4235. Published at The Patent Office, 25 Southampton Buildings, London, WC2A lAY, from which copies may be obtained.