AU663895B2 - Control mechanism for latches and the like - Google Patents

Description

I rAiJI"i-^" a, P/01/009 Regulation 3.2

AUSTRALIA

Patents Act 1990 68389~

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT I certify that the following 20 pages are a true and correct copy of the description and claims of the original complete specification in respect of an invention entitled: CONTROL MECHANISM FOR LATCHES AND THE LIKE 0 0 o o o o a o e o 0 0 0 0* 00 0 0 C 0 0 0 Name of Applicant PERIDA PTY LIMITED 6&"t V/ Signature 21510C/454 -2 CONTROL MECHANISM FOR LATCHES AND THE LIKE i The present invention relates to control mechanisms j for latches and the like and will be described with i particular reference to uE. in a cattle crush, but the invention is equally applicable to other machinery where analogous latching requirements exist.

A cattle crush has a steel framework defining a narrow channel into which a beast is forced to walk, and the beast is then clamped in the cattle crush so that any necessary veterinary and other treatment processes can be conducted safely with the beast suitably restrained. A cattle crush has a pair of panels or doors at the head end, which are moved into engagement with the opposite sides of the neck of the beast so as to restrain the head. Secure latching in the clamping position is required as considerable forces can be exerted by a beast. Furthermore, adjustment of the latching position is necessary to accommodate beasts of different sizes and for this reason conventional cattle crushes use a ratchet and pawl arranged so that the pawl engages the ratchet as 4 an operating handle is moved to close the doors around the neck of the beast. A release lever is provided to disengage the pawl so that the handle can be moved back d to the open position.

In the prior art it is necessary for the operator to Sactuate two separate mechanisms to enable opening or closing of the cattle crush doors. One mechanism must be j actuated to release the latch mechanism, at least in the opening direction, and then another mechanism must be actuated to cause motion of the doors. The latch is usually released by the operator actuating a release lever, a "trigger" for which is positioned in close association with the operator handle. Broadly, the present invention is directed towards new and useful control mechanisms, which can be advantageously employed in a variety of machines and in particular can produce improved convenience, safety and versatility with the 454/S:21510C130.10.92

L.

i L i l- i-lu~- NICi

F

b, oa o o o 0 o o 0 0 0 00 1 3 potential for ease of release even when a considerable pressure is being exerted on a latching mechanism such as a pawl of a ratchet and pawl. The control of ratchet and pawl mechanisms is one particularly important and useful application of the present broad inventive concept, but the invention is not limited to this field.

According to the present invention there is provided a control mechanism for controlling movement of movable first and second parts of an apparatus between first and second positions and for holding the parts in the first position, the mechanism comprising a linkage mechanism actuatable to move the parts between the first and second positions, and an operator handle movable by an operator and associated with the linkage mechanism so that motion of the operating handle is transmitted by the linkage mechanism to cause the movement of the first and second parts, the linkage mechanism comprising a latching mechanism adapted to hold the parts in at least the first position, the linkage mechanism being arranged so that the motion of the operating handle in a least one direction causes release of the latch mechanism and movement of the parts from the first to the second positions.

The linkage mechanism further comprises a movable actuating arm adapted to displace the movable parts, and the latching mechanism comprises a latch element associated with the movable actuating arm and displaceable therewith and a latching structure adapted to be engaged by the latch element at least when the parts are in the first position, the latch element being biased to enter latching engagement to hold the parts in the first position, the actuating arm comprising first and second relatively displaceable portions, the first portion being adapted to be displaced through a limited range of motion relative to the -econd portion in response to motion of the operating handle to disengage the latch element from the latching structure and thereafter to transmit motion to the second portion to cause, when in use, the movable parts to be moved from the first position to the second position, the structure being such that when the operating handle is released,

NAL

S:215100/16,08,95/438 L 4 there is relative motion between the first and second portions of the actuating arm whereby the latch element is released to engage with the latching structure, and return motion in the opposite direction of the operating handle causes displacement force to be transmitted through the first portion to the second portion to cause the parts to be moved from the second position to the first position, and when the parts reach the first position the latch element engages the latching structure under its biasing force.

Preferably the latch element is a pivotal pawl mounted on the second portion and spring biased to engage the latching structure, and the latching structure is in the form of a ratchet.

Most advantageously the invention can be implemented in a structure in which at least a portion of the linkage mechanism moves in an arcuate manner and wherein the operating handle is elongate and provides substantial leverage for operating the device and moving the linkage in an arcuate manner. The latching structure is preferably in the form of an arcuate ratchet and the actuating arm is preferably in the form of pivotally displaceable and interconnected arm portions.

The operator handle is preferably engageable and disengageable with the linkage mechanism prior to movement of the parts. The operator handle is preferably arranged to return to a "retirement position" on disengagement from the linkage mechanism and release by the operator. In the retirement position the operator handle is preferably in an unobtrusive position where it provides minimal obstruction to an operator of any apparatus associated with the control mechanism and first and second movable parts eg. a cattle crush.

The operating handle preferably relies on gravity to cause return to the retirement position. The retirement position will preferably be one in which the operating handle is vertical.

Particularly for application to a cattle crush, the 454/S:21510C/30.10.92 operating mechanism may be designed to rely on gravity so that motion of the handle in an upward direction moves the parts to the second position (in which the cattle crush is open) and the handle is generally horizontally directed. Preferably the handle is pivotally mounted so that it swings down under its own weight to be safely portioned in a vertical direction (retirement position); the handle is simply swung up to the horizontal position and then engaged with the linkage mechanism, for example by a simple rectilinear motion so that downward motion of the handle then displaces the linkage mechanism downwardly with (where the latching mechanism comprises a ratchet and the latching element a pawl) the pawl jumping over the ratchet whereby latching engagement is maintained through the pawl as the parts are moved i.e.

to close the doors around the neck of the beast.

Preferably, the mounting arrangement of the handle is such that no rectilinear motion is necessary to enable the handle to engage the operating mechanism to cause the cattle crush doors to open. Mere upward motion of the handle will cause engagement with the operating mechanism and opening of the doors. The rectilinear motion is only necessary to cause the handle to engage with the operating mechanism to enable the doors to close.

The handle is very important in providing leverage to facilitate disengagement of the pawl.

An important advantage of at least the preferred embodiment of the present invention, is that the latch mechanism is released and motion is transmitted to the movable parts by a single movement of the operating handle. There is no need for the operator to separately operate a release lever to release the latching mechanism, as in the prior art.

A further advantage of at least the preferred embodiment of the present invention, particularly for the cattle crush application, is when the operating handle is in the retirement position (vertical) it does not obstruct the person working on the beast held in the 454/S:21 510C/30.10.92 i -6cattle crush. With conventional cattle crushes, the operating handle protrudes outwardly from the cattle crush and can obstruct the person. From a safety point of view, the likelihood of injury of a person operating the cattle crush is reduced with the preferred embodiment of the present invention.

In the preferred embodiment of the invention as applied in a cattle crush an extension bar or tube runs along the cattle crush from the operating mechanism to an auxiliary operating handle provided mounted remotely from the operating handle, so the operator can open or close the cattle crush from either end. This facilitates one man handling of beasts with efficient throughput and the structure can be manufactured economically in a durable manner.

For illustrative purposes only an embodiment of cattle crush will now be described with reference to the accompanying drawings which illustrate schematically the C G cattle crush and its components.

In the drawings:- Figure 1 is an illustration of the general arrangement viewed from the side of the cattle crush; Figure 2 is an illustration of the general arrangement o ,i viewed from the head end of the cattle crush; Figure 3 is a plan view of an actuating arm for a linkage of the preferred embodiment; Figure 4 is an elevation of the actuating arm of figure 3 and figure 4A is an end view of the elevation of figure 4; Figure 5 is a plan view of a latching linkage controlled by the actuating arm of figures 3 and 4 and showing the latching linkage mounted in association with an arcuate ratchet; Figure 6 is an elevation of the latching linkage of figure 5 but omitting the ratchet; Figure 7 is an elevation of the ratchet as shown in figure 5; and Figure 8 is an elevation of an operating handle unit for 454/S:21510C/30.10.92 '-9 -7- 0 4 0 00 o

I

000( 00 0 0 0 mounting on and operating the actuating arm of figures 3 and 4.

Referring first to figures 1 and 2, the general arrangement of a cattle crush is illustrated, but without including details of the control mechanism embodying the present broad invention. A cattle crush is generally constructed comprising side frameworks 10 spaced apart by upper framework 11 and having at the head end a pair of sliding doors 12, which are suspended on mounting straps 13, which have rollers (not shown) at the upper end and supporting the doors for movement along a track incorporated in the upper framework 11.

A linkage mechanism includes a rocker arm 14 mounted on the upper framework about a main pivot bolt 15, the opposite ends of the arm being pivotally connected to push rods 16 and 17, which are connected to the respective doors so that clockwise rotation of the rocker arm 14 moves the doors towards one another so as to engage in opposite sides of the neck of a beast and moved in the opposite direction opens the doors.

Figure 1 schematically shows a control and latching mechanism which also form part of the linkage mechanism, and incorporates a latching linkage and an actuating arm at the head end of the cattle crush. A pivotally mounted 25 operating handle 18 is provided at the head of the crush for engagement with an actuating arm and a second handle 19 is provided the tail end of the cattle crush to operate through a crossbar IIA to control the linkage mechanism at the head end as an alternative to operating 30 the handle 18.

The overall scheme is that a ratchet 21 is rigid and arcuate with a set of teeth 22 schematically shown in figure 7. The ratchet is fixed to a main frame element of the cattle crush and carries in its upper region a pair of spacer blocks 23 on each side with a bore 24 extending through the structure for accommodating the main pivot bolt. A latching linkage 25 (shown in figures and 6) and an actuating arm 26 (shown in figures 3 and S:21510 OD/16.08.95/438 i i j i C ii!

$:I

i_ _Y l -8o o 4) are mounted off this pivot bolt, which passes through the rocker arm 14, (conveniently formed of square section steel tubing). The actuating arm 26 is engaged selectively by the operating handle 27 shown in figure 8 (18 of Figure 1) Referring now to figures 5 and 6, the latching linkage 25 comprises a pair of parallel side plates 28 interconnected by an end plate 29 and pivotally mounted over the main bolt 15 which passes through bores 30 of plates 28 and bores 24 of blocks 23. A pawl 31, as the latch element, is pivotally mounted about a cross-bolt 32, the pawl comprising a main strip 33 and a square section head 33A with a tip 34 for engaging :he ratchet.

The head also carries a cross pin 35 on one end of which a bolt 36 is secured to anchor the free end of a helical Sextension spring 37. The spring is shown in an extended condition in figure 5 for ease of illustration, but normally pulls the tip 34 of the pawl into engagemen, -with the ratchet 21.

S 20 A lateral extension 39 of the cross-pin 35 is o0 opositioned for engagement with the actuating arm 26, (see .o figure which will now be described with reference to figures 3 and 4.

The actuating arm 26 is an assembly of components, is rigid, and has a pair of side plates 40 and 41, interconnected by a rigid pin 42 and an end plate 42A.

The plates also have a hole 43 through which the main bolt 15 passes. Side plate 40 in use lies vertically alongside the side plate 28 of the latching linkage shown in figure 5, with this side plate slidable into and out of a slot 49 (as shown in figure 4A by arrow A leading bevel edge 44 of side plate 40 is positioned to lie adjacent the extension 39, so that upward movement of the actuating arm 26 relative to the latching mechanism 25 causes the bevel edge 44 to engage the extension 39 until it moves down the bevel to engage lateral portion 44A (see figure 4) lifting the pawl out of latching .7 engagement with the ratchet. Through engagement with the :!.'S:2151 0D/16.08.9 51438 t r I I I I, I 1 r- ;ii 4;1 _i 1 ~mrrnt&i -9o o S 0000 o 0 0000 ooo0 o~ o o o I 0 Q 00 0 4 "0 0 00 extension 39 on the lateral portion 44A, upward force is transmitted from the actuating arm of figures 3 and 4 to the latching linkage 25 and through to the rocker arm 14, whereby the doors of the cattle crush are opened.

Rocker arm 14 is welded to a face of one of the side plates 28 of the latching linkage 25 so that motion of the latching linkage is transmitted directly to the rocker arm 14.

A transverse member having legs 45 and 47 and a top plate 46 is welded to the outer face of side plate 40 of the actuating arm 26. Downward motion of the actuating arm 26 relative to the latching mechanism 25 causes the plate 46 to engage the upper surface 28A of the side plate 28 of the latching linkage 25. In this position, the pawl is released and engages the ratchet under spring biEsing. Further downward motion of the actuating arm 26 causes motion to be transmitted to the rocker arm 14 to cause the doors to close. The ratchet and pawl mechanism are arranged such that the pawl slides over the 20 ratchet when motion of the doors in the closing direction is occurring. The pawl only engages the ratchet to prevent motion in the opening direction, unless the pawl is lifted out of engagement with the ratchet first by upward motion of the actuating arm 26.

25 Referring to the handle shown in figure 8, it is formed from a first flat strip 50 connected to a parallel second strip 51 through a connection strip 52. The components are rigidly welded together and thus a generally H-shape is formed. In use the handle is inserted vertically so as to drop over pin 42 shown in figure 3 with a strip 50 located in the central region 26A of the actuating arm 26. The handle can pivotally move and is normally vertical. To operate the device, the handle is manually swung outwardly and upwardly and thus rotates around pin 42 until the surface 51A engages the main bolt 15 running through hole 43. To close the cattle crush doors, the handle is firstly then moved rectilinearly (in the direction of arrow B, figure 8) so 0 00 0 4 044

I

I J*: S:21510D/1 6.08.95/438 ~iI i ~i 10 00 0 g o o o o 0 0 000o 0 o0 oo a a u 0000 0o o 0 0 0 0( 00 00 0 00 0 that the bolt 15 adopts the position shown in dotted lines in figure 8. The handle is then latched in position and secondly can be used as a lever, downward motion thereof causing the doors of the cattle crush to close. The handle can also be simply released to swing down independently to a safe vertical position, which avoids injury to personnel in the region of the cattle crush.

To open the doors no initial rectilinear motion of the handle 27 is necessary to engage the main bolt Arcuate motion from the vertical position of the handle 27 will automatically cause the left upper arm of the Hshaped plate to engage the bolt 15, as this arm is longer than the other arm. Continuing upward arcuate motion will cause the cattle crush doors to open, as the actuating arm 26 causes the pawl to be disengaged from the ratchet, further motion causing the doors to open.

Referring again to Figure 1, the handle 19 at the remote end of the cattle crush from the operating 20 mechanism is connected to the actuating arm 26 by crossbar 11A. The connection is shown in ghost outline on Figure 3. Motion of the remote hana 19 is therefore transmitted to the actuating arm 26 by ,he cross-bar 11A.

The doors can thus be opened and closed by the remote handle 19, operating through actuating arm 26. The operating handle 19 is connected to operate the cross-bar 11A by way of a similar mechanism which connects the operating handle 18 to the actuating arm 26. In other words, an H-shaped plate is provided at the connecting end of the operating handle 19 and a pair of pins are provided to allow the handle to be engaged or disengaged with the cross-bar 11A and to enable it to return to a vertical retirement position on disengagement. The connection may be by means of a plate with a pair of pins welded thereto on one side and the cross-bar 11A welded thereto on the other side.

In prior art cattle crushes it has always been necessary for at least the handle at the operating end of the crush to be permanently fixed to the operating 40 mechanism, so that as the crush doors are opened or >rf S:2151D/ .08.95/438 SS:21510D1 6.08. 95/438 r closed the operating handle swings through its full arc.

Where the doors are only partially closed, therefore, such as when the head of a large beast is immobilised between the doors, the operating handle may jut out from the crush creating a safety hazard. The operating handle has previously always been permanently engaged with the operating mechanism because of the need for a release lever to enable release of the latching mechanism. The release lever usually comprises an actuatable grip mechanism which the operator must actuate at the same time as he moves the handle to enable the cattle crush doors to be opened. In the present invention, the release mechanism is remotely operable, and the latch is caused to release by the motion of the operator handle which also causes the cattle crush doors to open. There is no need for a separate lever mechanism. This means that the handle can be mounted in a disengageable fashion j with the operating mechanism. Further, the cattle crush doors can also be opened by the handle remote from the operating mechanism. This was not possible in the prior art.

Whilst the invention has been described with reference to a particular embodiment it will be appreciated that the invention can be embodied in many other forms.

Variations and modifications may be made in respect of the invention as above described and defined in the following statement of claims: SI o h neto saoedsrbdaddfndi h 454/S:21510C/30.10.92 r i

Claims (8)

1. A control mechanism for controlling movement of movable first and second parts of an apparatus between first and second positions and for holding the parts in the first position, the control mechanism comprising: a linkage mechanism actuatable to move the parts between the first and second positions; an operator handle movable by an operator and associated with the linkage mechanism so that motion of the operating handle is transmitted by the linkage mechanism to cause the movement of the first and second parts; the linkage mechanism comprising: a latching mechanism adapted to hold the parts in at least the first position, and o (ii) a movable actuating arm adapted to displace the movable parts, and wherein the latching mechanism comprises: a latch element associated with the S0 20 movable actuating arm and displaceable therewith, (ii) a latching structure adapted to be engaged by the latch element at least when the parts are in the first position, 25 (iii) the latch element being biased to enter latching engagement to hold the parts in the first position; the movable actuating arm comprising first and second relatively displaceable portions; the first portion being adapted to be displaced through a limited range of motion relative to the second portion in response to motion of the operating handle to disengage the latch element from the latching structure and thereafter to transmit motion to the second portion to cause, when in use, the movable parts to be moved from the first position to the second position; the structure be2--( such that when the operating 0i K r p*- i: i. i. 13 handle is released, there is relative motion between the first and second portions of the movable actuating arm whereby the latch element is released to engage with the latching structure; return motion in the opposite direction of the operating handle causes displacement force to be transmitted through the first portion to the second portion to cause the parts to be moved from the second position to the first position; and when the parts reach the first position the latch element engages the latching structure under its biasing force.

2. A control mechanism in accordance with claim 1, wherein the latch element is a pivotal pawl mounted on the second portion and spring biased to engage the latching structure, and the latching structure is in the form of a ratchet.

3. A control mechanism in accordance with claim 2, Swherein the first portion of the actuating arm is d r 20 provided with a bevel edge adapted to abut a projection of the latch element when the operating handle is moved to cause the parts to be moved from the first position to o the second position, the bevel edge acting on the latch o, element projection to disengage the latch element from 1 25 the latching structure during the motion of the parts 0 from the first to the second positions. S4. A control mechanism in accordance with any of Si the preceding claims, wherein the operating handle is movable by the operator to engage the linkage mechanism prior to movement of the movable parts, the operating handle being biased to return to a retirement position on disengagement from the linkage mechanism and release by the operator. S:21510D/16.08.95/438 -7 arncrr~F~ 14 A control mechanism in accordance with claim 4, wherein the operating handle is pivotally mounted with respect to the linkage mechanism and arranged to swing under its own weight to a substantially vertical retirement position when disengaged from the linkage mechanism and released by the operator.

6. A control mechanism in accordance with claim wherein the operating handle is elongate and one end thereof is in the form of a substantially H-shaped plate, the operating handle being mounted with respect to the linkage mechanism by means of the H-shaped plate, the linkage mechanism being provided with first and second pins adapted to engage respectively between the lower and upper pairs of arms of the H-shaped plate when the operating handle is engaged with the linkage mechanism, 00 the lower arms only of the H-shaped plate being engaged So0o only be the first pin when the handle is disengaged from 0 othe mechanism whereby the handle is freely, pivotally supported. 00 0 0 0 o 20 7. A control mechanism in accordance with claim 6, wherein the operating handle and the linkage mechanism are substantially as herein described with reference to o0 the accompanying drawings. 0000 S 0 8. A control mechanism in accordance with any oo°0 25 preceding claim, wherein at least a portion of the linkage mechanism is adapted to undertake an arcuate motion in order to move the parts, the operating handle 00 being elongate and adapted to provide substantial 30 leverage for the operator to transmit the arcuate motion to the linkage mechanism.

9. A control mechanism in accordance with claim 8, wherein, latching structure is in the form of an arcuate ratchet and the actuating arm is in the form of pivotally i displaceable and interconnected arm portions. A: S:2151 D/1 6.08.95/438 r 15 A control mechanism in accordance with any preceding claim, wherein the first and second parts are first and second slidably mounted doors and motion is transmitted by the linkage mechanism to the doors to either slide them together in a closing direction or slide them apart in an opening direction.

11. A cattle crush, comprising a frame defining a channel for holding a beast, and first and second doors at one end of the frame, mounted and adapted to be moved between first, adjacent positions for holding a neck of a beast between opposed edges of the doors and second speed portions in which the beast is free, and a control mechanism in accordance with any of claims 1 to wherein the first and second doors provide the first and second parts.

12. A cattle crush in accordance with claim 11, and further comprising an auxiliary operating handle mounted on a part of the cattle crush frame remote from the operating handle, and transmission means associated with the auxiliary operating handle for transmitting motion of the handle to the linkage mechanism to enable the doors to be opened or closed by operation of the auxiliary operating handle. 3.3. A control mechanism substantially as described 25 herein with reference to the accompanying drawings.

14. A cattle crush substantially as described herein and substantially as shown in the accompanying drawings. i if i i I i y f B; Dated this 16th day of August 1995 CARINYA PRODUCTS By their Patent Attorneys GRIFFITH HACK CO S:21 51 OD/1 6.08.95/438 'A H ABSTRACT A CONTROL MECHANISM FOR LATCHES AND THE LIKE The present invention relates to a control mechanism for latches and in particular to a control mechanism for controlling the opening and closing of slidably mounted doors of a cattle crush or a similar structre. i! An operating handle is movable by an operator to act on a linkage mechanism communicating with the slidably mounted doors. The linkage mechanism includes a latching mechanism which holds the doors in the desired position after the operator handle has been released. Motion of the operating handle has two effects. Firstly, the motion of the operating handle is transmitted via the linkage mechanism to open and close the doors. Secondly, the motion of the operating handle causes the latch mechanism to be released to enable motion of the doors. There is no requirement for the operator to separately actuate a separate means for releasing the latching mechanism. V S:21 510D28.06.95/429