GB2330324A

GB2330324A - Cam actuated suction device

Info

Publication number: GB2330324A
Application number: GB9721937A
Authority: GB
Inventors: Michael Ritson; Ronald Price Hickman
Original assignee: Maurice Willis
Current assignee: Maurice Willis
Priority date: 1997-10-16
Filing date: 1997-10-16
Publication date: 1999-04-21
Anticipated expiration: 2017-10-16
Also published as: GB2330324B; GB9721937D0

Abstract

A suction device 11 comprises a flexible disc 12, a support cup 13 having a concave portion facing the disc 12, a camming arrangement 14 on the opposite side of the support cup 13 to the disc 12, and a connecting rod 19 passing through the support cup 13 and connecting the disc 12 to the camming arrangement 15. Operation of the camming arrangement 15 moves the connecting rod 19 and draws the central area of the disc 12 into the concave portion of the support cup 13. The camming arrangement includes first and second cam members 15,16 which have engaging cam surfaces 31,39. The first cam member 15 is movable in an arcuate path in a plane generally parallel to the plane of the disc 12.

Description

Suction Device The present invention relates to a suction device, in particular, a suction device capable of attachment, through suction, to a smooth surface which may be planar or gently curved in one or more senses.

Known suction devices of this general nature are used to lift sheets of planar and curved glass, and also metal panels and other articles with a smooth surface finish. They typically comprise a round flexible disc, a support cup with a smaller diameter than the disc and a cam lever.

A shaft connected to the centre of the disc passes through a hole in the support cup and is pivotally connected to the cam lever. The cam lever has a cam surface which is eccentric relative to the pivot axis so that movement of the cam lever in an arc at right angles to the plane of the disc brings the cam surface into engagement with a follower plate on the support cup.

This engagement lifts the shaft which in turn draws the central region of the disc into the support cup.

If this operation is carried out with the disc in contact with a smooth surface, it will tend to cause a vacuum between the disc and the surface in the central region of the disc, while the outer periphery of the disc forms a seal with the surface. Ambient atmospheric pressure then keeps the suction device in place.

These devices are perfectly adequate in most applications. However, when there is a restricted access to the area in the region of the support cup on the side opposite to the disc, the device can be difficult or impossible to operate. This is due to the arcuate movement of the cam lever in this area. In addition, in some applications, the area behind (as it were) the support cup is required for certain other functions which the cam lever would tend to interfere with.

It is therefore an object of the present invention to provide a suction device in which the area behind the support cup is unimpeded.

According to the invention, there is provided a suction device comprising: a flexible disc; a support member having a concave portion facing the disc; a camming arrangement on the opposite side of the support member to the disc; and a connecting member passing through the support member and connecting the disc to the camming arrangement, whereby operation of the camming arrangement moves the connecting member and draws the central area of the disc into the concave portion of the support member; and in which the camming arrangement includes first and second cam members which have engaging cam surfaces, the first cam member being movable in an arcuate path in a plane generally parallel to the plane cf the disc.

This construction eliminates the need for any operative components in the area behind the camming mechanism.

Preferably, the disc is made of rubber or a plastics material. Preferably the support member is in the form of a rigid circular cup of metal or plastics whose rim engages the rear surface of the disc and whose diameter is smaller than the diameter of the disc. Thus, when the control area of the disc is drawn into the cup, the protruding outer periphery of the disc maintains contact with the surface of the article which is to be engaged by the suction device, and permits the suction device to adhere positively not only to flat surfaces but to curved surfaces also. The device is even applicable to surfaces which are curved in more than one direction, for example vehicle windows.

Preferably, the connecting member is a rod which is attached to the disc. Preferably, the camming arrangement includes an operating lever connected to and extending generally radially from the first cam member, whereby movement of the lever causes the first cam member to follow its arcuate path. Conveniently, the first cam member has an arcuate cam profile defining its cam surface while the second cam member is a cam follower and is connected to the connecting member. Alternatively, the first cam member may constitute the cam follower and the second cam member may define a stationary profiled cam surface.

Preferably, the connecting member is a square crosssection rod which passes through a correspondingly square shaped hole in the support member, and which is rigidly attached to the disc at one end, and which is nonrotatably attached to the second cam member. Crosssectional shapes other than square may be used, though if the rod is to be prevented from rotating, round crosssection is preferably avoided.

Preferably, the arcuate cam profile of the first cam member is coaxial with and extends about the rod, whereby an arcuate movement of the handle causes the arcuate cam profile to follow its arcuate path which in turn causes the cam follower to move in the axial direction without any rotation, thereby drawing the central area of the disc into the concave portion of the support member. In a preferred embodiment, the arcuate cam profile comprises a pair of similar ramps following part circular paths in the same sense and at the same radius, the paths extending between a low position and a high position, and in which the second cam member comprises a pair of bosses which constitute the cam follower, attached to a common base, the base being non-rotatably attached to the rod by means of a pin passing through both the rod an the base.

Thus, when the disc is in a relaxed condition, it is slightly spaced from the support cup and the bosses lie on the ramps at the low positions. As the lever is moved through its arc, the first cam member rotates with it, and the ramps follow their circular path. The bosses which are rotationally fixed, travel along their respective ramps from the low position to the high position and in so doing move the rod axially rearwards.

This in turn draws the central area of the disc into the cup, so tending to form a vacuum between the disc and any smooth surface with which the disc may be in contact.

The vacuum is then released by reversing the operation.

The device may include a cover over the camming arrangement, which may be detachably connected to the first camming member. The device may also include a compression spring acting between the rear of the disc and the inside of the support cup, the spring acting to bias the disc away from the support member.

Preferably, the surface of the support member which engages the disc is provided with one or more protuberances, the protuberances being arranged to deform the resilient material of the disc on engagement, thereby positively preventing any significant relative rotational movement between the disc and the support member. This is a very important feature, for example where the device is to be used to support an article from a generally vertical surface, particularly when it is important that the article should be prevented from tilting or rotating to one side or the other.

The suction device may therefore form part of another device which may need to be temporarily attached to a surface. Alternatively the device may simply have a handle attached, for example, to the support member.

The disc preferably has at its centre a rounded protrusion which serves several purposes. Firstly, when the suction device is offered up to a rigid surface to which it is to be attached, moderate pressure applied by the operatcr's hand causes the protrusion to cause an initial slight dishing of the disc as the disc bears against the support member on an annular contact ring inboard of the extreme periphery of the disc. Further pressure causes the disc to be seated against the rigid surface to which it is to be attached. This seating may occur at the periphery of the disc (especially in the event of its meeting a convex surface) or in line between the support member and the rigid surface (especially if meeting a flat or flatter surface). The resultant contact of the disc at or near its periphery throughout 360 , plus the slight displacement (hollowing) of the "rubber" disc, causes a small amount of air to be expelled resulting in a relatively negative air pressure between the disc and the surface. This minimal negative air pressure is however not sufficient to do more than seal the disc onto a flat or slightly curved rigid planar surface. With the initial sealing having been effected, however, when the centre of the disc is drawn back by operation of the lever, the negative air pressure will increase.

A second purpose of the protrusion is to avoid what may be termed "phantom suction" that is to say, the tendency of the disc to adhere when it is placed at rest on a flat surface.

A third purpose of the protrusion is to assist in removal of the device. If the protrusion were not present, there would be a potential that after reversing the action of the lever, some adhesion and/or residual suction might develop between the rubber disc and the rigid surface to which it was attached, and the device might stay adhering for a few second and then fall off.

However, the protrusion helps to break the residual adhesion, so that when the lever is reversed, the device will detach under gravity into the control of the operator.

The invention may be carried into practice in various ways and one embodiment will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is an exploded perspective view of a suction device according to the invention; Figure 2 is a perspective view of the support cup from the front with an enlarged detail; Figure 3 is a perspective view of the two cam members in engagement; Figures 4a and 4b are a rear view and side view of the cam members in the relaxed or non-activated position; Figures 5a and 5b are views similar to Figures 4a and 4b but in the activated position; Figure 6 is a vertical section through the suction device prior to activation; and Figure 7 is a view similar to Figure 6 but after activation and attachment to a surface.

Referring to Figure 1, a suction device 11 comprises a flexible rubber disc 12, a metal or rigid plastics support cup 13, a camming mechanism 14 including a first cam member 15 and a second cam member 16, a cover 17 and a handle 18. The disc 12 is circular and has a square section metal rod 19 protruding rearwards from its centre. The rod 19 is fixed to a rigid plate (not shown) which is embedded in the disc 12. The front surface of the rigid plate is fixed to the disc 12, which the rear surface of the rigid plate, from which the rod 19 extends, is not. This allows relative movement between the material of the disc 12 and the rigid plate which is important when the device is activated and the disc adopts its concave position.

The support cup 13 has a circular rear wall 21 and a peripheral collar 22 but has a smaller diameter than the disc 12. It has a circular recess 23 in the rear wall 21, and a square hole 24 in the recess 23. A side plate 25 extends laterally from each side of the collar 22, each side plate 25 having a tab 26 with a pair of holes 27.

The first cam member 15 is a generally cylindrical member 28 having a slightly smaller diameter than the recess 23. The rear circular rim 29 of the member 28 defines a cam surface which comprises two ramps 31, each extending in the same sense (anti-clockwise in Figure 1) from a low position 32 to a high position 33. Each ramp 31 extends through an arc of about 90 . A lever 34 extends radially from the cylindrical member 28 and has a tapped hole 35 at its base.

The second cam member 16 comprises a thick circular disc 36 with a square central hole 37. A bore 38 extends from one side of the disc 36 through to the other side, notionally extending through the square hole 37. A circular boss 39 protrudes radially outwards from each side of the disc 36. The diameter of the disc 36 is slightly smaller than the internal diameter of the cylindrical member 28.

The cover 17 is conical with a rounded apex and a slot 41 in its periphery. It also has a countersunk hole 42 near the rounded apex. The handle 18 comprises a cylindrical cross member 43 and two side members 44 each with a pair of holes 45.

Referring now to Figure 2, the front edge of the collar 22 of the support cup 13 has a pair of diametrically opposite studs 46. The studs 46 face towards the disc 12.

When fully assembled, the rod 19 on the disc 12 passes through the square hole 24 in the support cup 13 via a light compression spring 47 (which is optional) and then on to the cam arrangement 14. The cylindrical member 28 of the first cam member 15 fits into the recess 23 in the support cup 13 with a washer 48 spaced between the components. The rod 19 is located in the square hole 37 in the disc 36 and is held in position by a pin 49 which is inserted into the bore 38 and passes through a hole 51 in the rod 19.

The disc 36 fits within the cylindrical member 28 (as shown in Figure 3). The circular bosses 39 lie on the ramps 31 and are movable between the respective low positions 32 and high positions 33. The dimensions of the components and the position of the hole 51 are arranged so that when the device is assembled, with the bosses 31 at the low positions 32 the disc 12 is spaced from the rim of the support cup 13 by a small distance 52 (as shown in Figure 6), the spacing being maintained evenly by the optional spring 47.

The cover 17 is attached by means of a screw or bolt (not shown) which is inserted into the hole 35 in the first cam member 15 via the countersunk hole 42. The handle 18 is attached by means of screws or bolts (not shown) which are inserted into the holes 27 via the holes 45 in the side members 44. The handle 18 is located immediately over the centre of the disc 12.

Activation of the device will be described with reference to Figures 4 to 7. When the device is to be activated, the lever 34 is moved from the position shown in Figures 4a, 4b and 6 to that shown in Figures 5a, Sb and 7 (arrow A). In so doing, the first cam member 15 is rotated through about 90", about the axis of the rod 19.

The second cam member 16 is restrained from rotation by the square sectioned rod 19 which is located in the square hole 37 and which is itself held against rotation by the square hole in the cup support 13. The bosses 39 are therefore constrained to follow the ramps 31 as they move through their respective arcs to the position shown most clearly in Figures 5a and 5b. In following the ramps 31, the bosses 39 move axially rearwards (to the left in Figures 4b and 5b), thereby moving the second cam member 16 itself rearwards. This takes with it the rod 19 (arrow B).

As the rod 19 moves rearwards, it draws the central part of the flexible disc 12 into the support cup 13.

If, prior to this operation, the disc 12 is presented (arrow C) to a smooth surface, such as a curved window 53 as shown in Figures 6 and 7, the drawing-in of the central part of the disc 12 initially brings the periphery of the disc 12 into contact with the window.

This operation is facilitated by the location of the handle 18 over the centre of the disc 12. Continued operation of the lever 34 moves the rod 19 and the central part of the disc 12 away from the window, causing a vacuum in space created 54. Atmospheric pressure then holds the suction device 11 in place on the window 53 until the operation is reversed.

In order to assist in locating the disc 12 initially against the window, the disc 12 has a rounded protrusion 55. As the protrusion is brought into contact with a surface, it is pushed inwards and so starts the sealing operation. It also assists in breaking the suction when the device is de-activated and helps to hold the device in position when the vacuum is released.

In order to prevent any small relative rotational movement between the disc 12 and the support cup 13 (and therefore the handle 18), the studs 46 shown in Figure 2 are provided. When the front rim of the support cup 13 is brought into contact with the disc 12, the studs 46 dig into the resilient material of the disc 12. This engagement positively prevents any relative rotational movement between the disc 12 and the support cup 13.

It will be appreciated that the flexibility of the disc 12 together with the depth of the concavity of the support cup 13 and the relative diameters of the disc 12 and support cup 13 enable the suction device to be used effectively not only on flat surfaces but also on surfaces which are curved in one or more senses.

Claims

Claims: 1. A suction device comprising: a flexible disc; a support member having a concave portion facing the disc; a camming arrangement on the opposite side of the support member to the disc; and a connecting member passing through the support member and connecting the disc to the camming arrangement, whereby operation of the camming arrangement moves the connecting member and draws the central area of the disc into the concave portion of the support member; and in which the camming arrangement includes first and second cam members which have engaging cam surfaces, the first cam member being movable in an arcuate path in a plane generally parallel to the plane of the disc.
2. A suction device as claimed in Claim 1, in which the disc is made of rubber.
3. A suction device as claimed in Claim 1 or Claim 2, in which the support member is in the form of a circular cup whose rim engages the rear surface of the disc and whose diameter is smaller than the diameter of the disc.
4. A suction device as claimed in any preceding Claim, in which the connecting member is a rod which is attached to the disc.
5. A suction device as claimed in Claim 4, in which the rod is attached to a rigid plate which is itself embedded in the material of the disc.
6. A suction device as claimed in any preceding Claim, in which the camming arrangement includes an operating lever connected to and extending generally radially from the first cam member, whereby movement of the lever causes the first cam member to follow its arcuate path.
7. A suction device as claimed in Claim 6, in which the lever, during its movement, does not translate bodily about its axis.
8. A suction device as claimed in Claim 6, in which the first cam member has an arcuate cam profile defining its cam surface while the second cam member is a cam follower and is connected to the connecting member.
9. A suction device as claimed in Claim 8, in which the connecting member is a square cross-section rod which passes through a correspondingly square shaped hole in the support member, and which is rigidly attached to the disc at one end, and which is non-rotatably attached to the second cam member.
10. A suction device as claimed in Claim 9, in which the arcuate cam profile of the first cam member is coaxial with and extends about the rod, whereby an arcuate movement of the handle causes the arcuate cam profile to follow its arcuate path which in turn causes the cam follower to move in the axial direction without any rotation, thereby drawing the central area of the disc into the concave portion of the support member.
11. A suction device as claimed in Claim 10, in which the arcuate cam profile comprises a pair of similar ramps following part circular paths in the same sense and at the same radius, the paths extending between a low position and a high position, and in which the second cam member comprises a pair of bosses which constitute the cam follower, attached to a common base, the base being non-rotatably attached to the rod by means of a pin passing through both the rod an the base.
12. A suction device as claimed in any preceding Claim, further including a cover over the camming arrangement.
13. A suction device as claimed in Claim 12, in which the cover is detachably connected to the first cam member.
14. A suction device as claimed in any preceding Claim, further including a compression spring acting between the rear of the disc and the inside of the support cup, the spring acting to bias the disc away from the support member.
15. A suction device as claimed in any preceding Claim, in which the surface of the support member which engages the disc is provided with one or more protuberances, the protuberances being arranged to deform the resilient material of the disc on engagement, thereby positively preventing any significant relative rotational movement between the disc and the support member.
16. A suction device as claimed in any preceding Claim, further including a handle connected to the support member.
17. A suction device as claimed in Claim 16, in which the handle is positioned over the centre of the disc.
18. A suction device constructed and arranged substantially as herein specifically described with reference to and as shown in the accompanying drawings.